Online Etymology Dictionary

fair (adj.): Old English fæger "pleasing to the sight (of persons and body features, also of objects, places, etc.); beautiful, handsome, attractive," of weather, "bright, clear, pleasant; not rainy," also in late Old English "morally good," from Proto-Germanic *fagraz (source also of Old Saxon fagar, Old Norse fagr, Swedish fager, Old High German fagar "beautiful," Gothic fagrs "fit"), perhaps from PIE *pek- (1) "to make pretty" (source also of Lithuanian puošiu "I decorate").

The meaning in reference to weather preserves the oldest sense "suitable, agreeable" (opposed to foul (adj.)). Of the main modern senses of the word, that of "light of complexion or color of hair and eyes, not dusky or sallow" (of persons) is from c. 1200, faire, contrasted to browne and reflecting tastes in beauty. From early 13c. as "according with propriety; according with justice," hence "equitable, impartial, just, free from bias" (mid-14c.).

Of wind, "not excessive; favorable for a ship's passage," from late 14c. Of handwriting from 1690s. From c. 1300 as "promising good fortune, auspicious." Also from c. 1300 as "above average, considerable, sizable." From 1860 as "comparatively good."

The sporting senses (fair ball, fair catch, etc.) began to appear in 1856. Fair play is from 1590s but not originally in sports. Fair-haired in the figurative sense of "darling, favorite" is from 1909. First record of fair-weather friends is from 1736 (in a letter from Pope published that year, written in 1730). The fair sex "women" is from 1660s, from the "beautiful" sense (fair as a noun meaning "a woman" is from early 15c.). Fair game "legitimate target" is from 1776, from hunting.
Others, who have not gone to such a height of audacious wickedness, have yet considered common prostitutes as fair game, which they might pursue without restraint. ["Advice from a Father to a Son, Just Entered into the Army and about to Go Abroad into Action," London, 1776]
fair (n.): "a stated market in a town or city; a regular meeting to buy, sell, or trade," early 14c., from Anglo-French feyre (late 13c.), from Old French feire, faire "fair, market; feast day," from Vulgar Latin *feria "holiday, market fair," from Latin feriae "religious festivals, holidays," related to festus "solemn, festive, joyous" (see feast (n.)).
fair (adv.): Old English fægere "beautifully," from fæger "beautiful" (see fair (adj.)). From c. 1300 as "honorably;" mid-14c. as "correctly; direct;" from 1510s as "clearly." Fair and square is from c. 1600. Fair-to-middling is from 1829, of livestock markets.
fair-minded (adj.): 1754, from fair (adj.) + minded.
fair-spoken (adj.): mid-15c.; see fair (adj.) + -spoken.
fairground (n.): also fair-ground, 1741, from fair (n.) + ground (n.).
fairing (n.): "piece added for streamlining purposes," 1865, from fair (v.) a ship-building word meaning "to make 'fair' or level, adjust, make regular, correct curvatures," from fair (adj.).
fairly (adv.): c. 1400, "handsomely," from fair (adj.) + -ly (2). Meaning "impartially, justly" is from 1670s. Sense of "somewhat" is from 1805, a curious contrast to the earlier, but still active, sense of "totally" (1590s). Old English had fægerlice "splendidly."
fairness (n.): Old English fægernes "beauty;" see fair (adj.) + -ness. Meaning "even-handedness, impartiality" is from mid-15c. Meaning "lightness of complexion" is from 1590s.
fairway (n.): 1580s, "navigational channel of a river," from fair (adj.) + way (n.). Golfing sense is by 1898.
fairy (n.): c. 1300, fairie, "the country or home of supernatural or legendary creatures; fairyland," also "something incredible or fictitious," from Old French faerie "land of fairies, meeting of fairies; enchantment, magic, witchcraft, sorcery" (12c.), from fae "fay," from Latin fata "the Fates," plural of fatum "that which is ordained; destiny, fate," from PIE *bha- "to speak" (see fame (n.)). Also compare fate (n.), also fay.
In ordinary use an elf differs from a fairy only in generally seeming young, and being more often mischievous. [Century Dictionary]
But that was before Tolkien. As a type of supernatural being from late 14c. [contra Tolkien; for example "This maketh that ther been no fairyes" in "Wife of Bath's Tale"], perhaps via intermediate forms such as fairie knight "supernatural or legendary knight" (c. 1300), as in Spenser, where faeries are heroic and human-sized. As a name for the diminutive winged beings in children's stories from early 17c.
Yet I suspect that this flower-and-butterfly minuteness was also a product of "rationalization," which transformed the glamour of Elfland into mere finesse, and invisibility into a fragility that could hide in a cowslip or shrink behind a blade of grass. It seems to become fashionable soon after the great voyages had begun to make the world seem too narrow to hold both men and elves; when the magic land of Hy Breasail in the West had become the mere Brazils, the land of red-dye-wood. [J.R.R. Tolkien, "On Fairy-Stories," 1947]
Hence, figurative adjective use in reference to lightness, fineness, delicacy. Slang meaning "effeminate male homosexual" is recorded by 1895. Fairy ring, of certain fungi in grass fields (as we would explain it now), is from 1590s. Fairy godmother attested from 1820. Fossil Cretaceous sea urchins found on the English downlands were called fairy loaves, and a book from 1787 reports that "country people" in England called the stones of the old Roman roads fairy pavements.
fairy-tale (n.): "oral narrative centered on magical tests, quests, and transformations," 1749, translating French Conte de feés, the name given to her collection by Madame d'Aulnois (1698, translated into English 1699). As an adjective (also fairytale), attested by 1963.
fairyland (n.): also fairy-land, 1580s, from fairy + land (n.). Earlier simply Faerie (c. 1300).
fait accompli (n.): "a scheme already carried into execution," 19c., French, literally "an accomplished fact." See feat and accomplish.
faith (n.): mid-13c., faith, feith, fei, fai "faithfulness to a trust or promise; loyalty to a person; honesty, truthfulness," from Anglo-French and Old French feid, foi "faith, belief, trust, confidence; pledge" (11c.), from Latin fides "trust, faith, confidence, reliance, credence, belief," from root of fidere "to trust," from PIE root *bheidh- "to trust" (source also of Greek pistis "faith, confidence, honesty;" see bid). For sense evolution, see belief. Accomodated to other English abstract nouns in -th (truth, health, etc.).

From early 14c. as "assent of the mind to the truth of a statement for which there is incomplete evidence," especially "belief in religious matters" (matched with hope and charity). Since mid-14c. in reference to the Christian church or religion; from late 14c. in reference to any religious persuasion.
And faith is neither the submission of the reason, nor is it the acceptance, simply and absolutely upon testimony, of what reason cannot reach. Faith is: the being able to cleave to a power of goodness appealing to our higher and real self, not to our lower and apparent self. [Matthew Arnold, "Literature & Dogma," 1873]
From late 14c. as "confidence in a person or thing with reference to truthfulness or reliability," also "fidelity of one spouse to another." Also in Middle English "a sworn oath," hence its frequent use in Middle English oaths and asseverations (par ma fay, mid-13c.; bi my fay, c. 1300).
faith-healer (n.): Also faith healer, attested by 1874; from faith + healer. Faith-curer is from 1883.
The power which a man's imagination has over his body to heal it or make it sick is a force which none of us is born without. The first man had it, the last one will possess it. If left to himself, a man is most likely to use only the mischievous half of the force--the half which invents imaginary ailments for him and cultivates them; and if he is one of those very wise people, he is quite likely to scoff at the beneficent half of the force and deny its existence. [Mark Twain, "Christian Science," 1907]
faithful (adj.): early 14c., "sincerely religious, devout, pious," especially in reference to Christian practice; mid-14c., "loyal (to a lord, friend, spouse, etc.); true; honest, trustworthy," from faith + -ful. From late 14c. in reference to a tale, a report, etc., "accurate, reliable, true to the facts." The noun sense of "true believer, one who is full of faith" is from late 14c. (Church Latin used fideles in same sense). Related: Faithfully; faithfulness. Old Faithful geyser named 1870 by explorer Gen. Henry Dana Washburn (1832-1871), surveyor-general of the Montana Territory, in reference to the regularity of its outbursts.
faithless (adj.): c. 1300, "unbelieving," from faith + -less. Meaning "insincere, deceptive" is mid-14c. Related: Faithlessly; faithlessness.
faitor (n.): "impostor, cheat," mid-14c., from Anglo-French faiteor, faiture "evildoer; slothful person," apparently a specialized use of Old French faiture "sorcery, spell," literally "deed, action," from Latin facere "do, make, perform" (see factitious), an etymologically neutral term taken in a bad sense.
fajita (n.): by 1979, from Spanish fajita, diminutive of faja "bandage, wrapper," from Latin fascia "band, bandage" (see fascia).
fake: of unknown origin; attested in London criminal slang as adjective (1775 "a counterfeit"), verb (1812 "to rob"), and noun (1851, "a swindle;" of persons 1888, "a swindler"), but probably older. A likely source is feague "to spruce up by artificial means," from German fegen "polish, sweep," also "to clear out, plunder" in colloquial use. "Much of our early thieves' slang is Ger. or Du., and dates from the Thirty Years' War" [Weekley]. Or it may be from Latin facere "to do." Century Dictionary notes that "thieves' slang is shifting and has no history."

The nautical word meaning "one of the windings of a cable or hawser in a coil" probably is unrelated, from Swedish veck "a fold." As a verb, "to feign, simulate" from 1941. To fake it is from 1915, jazz slang; to fake (someone) out is from 1940s, originally in sports. Related: Faked; fakes; faking. The jazz musician's fake book is attested from 1951.
fakement (n.): "forgery," 1811, from fake (v.) + -ment.
faker (n.): 1846, agent noun from fake (v.).
fakir (n.): c. 1600, from Arabic faqir "a poor man," from faqura "he was poor." Term for Muslim holy man who lived by begging, supposedly from a saying of Muhammad's, el fakr fakhri ("poverty is my pride"). Misapplied in 19c. English (possibly under influence of faker) to Hindu ascetics. Arabic plural form fuqara may have led to variant early English forms such as fuckeire (1630s).
falafel (n.): by 1951 as a traveler's word, not common or domestic in English until 1970s; from Arabic falafil, said to mean "crunchy."
Falange: Spanish political party founded 1933 as a fascist movement; see Falangist. Related: Falangista.
Falangist (n.): 1937, member of the Falange, the fascist party in Spain (founded 1933), from Spanish Falange (Española) "(Spanish) Phalanx," from Latin phalanx (genitive phalangis); see phalanx.
Falasha (n.): "dark-skinned Jewish tribe of Abyssinia," 1710, from Ethiopian, literally "exiled, wanderer, immigrant," from falasa "he wandered."
falcate (adj.): "hooked, curved like a scythe or sickle," 1801, from Latin falcatus "sickle-shaped, hooked, curved," from falcem (nominative falx) "sickle," which is of uncertain origin, perhaps a borrowing from a non-Latin Indo-European language of Italy. De Vaan lists cognates as Old Irish delg "thorn, pin," Welsh dala "sting," Lithuanian dilge "nettle," Old Norse dalkr "pin, spine, dagger," Old English delg "clasp." Related: Falcated; falcation; falciform (1766).
falchion (n.): "a broad sword, somewhat curved," c. 1300, fauchoun, from Old French fauchon "curved sword," from Vulgar Latin *falcionem, from diminutive of Latin falx "sickle" (see falcate). Partially re-Latinized in early Modern English.
falcon (n.): mid-13c., faucon, from Old French faucon "falcon" (12c.), from Late Latin falconem (nominative falco) "falcon" (source also of Old Spanish falcon, Portuguese falcão, Italian falcone, Old High German falcho, German Falke, Dutch valk), probably from Latin falx (genitive falcis) "curved blade, pruning hook, sickle, war-scythe" (see falcate); the bird said to be so called for the shape of its talons, legs, or beak, but also possibly from the shape of its spread wings.

The other theory is that the Latin bird name falx is of Germanic origin and means "gray bird" (from the source of fallow (adj.)), which is supported by the antiquity of the word in Germanic but opposed by those who point out that falconry by all evidences was imported from the East, and the Germans got it from the Romans, not the other way round.
falconer (n.): late 14c., "one who hunts with falcons" (as a surname from late 12c.), from Old French fauconier "falconer" (Modern French fauconnier), from faucon (see falcon). Meaning "one who keeps and trains hawks" is from early 15c.
falconry (n.): 1570s, from French fauconnerie, from faucon (see falcon).
falderol (n.): also falderal, falderall, folderol, etc., 18c. nonsense words from refrains of songs; meaning "gewgaw, trifle" is attested from 1820.
fall (v.): Old English feallan (class VII strong verb; past tense feoll, past participle feallen) "to drop from a height; fail, decay, die," from Proto-Germanic *fallan (source also of Old Frisian falla, Old Saxon fallan, Dutch vallen, Old Norse falla, Old High German fallan, German fallen, absent in Gothic).

These are from PIE root *pol- "to fall" (source also of Armenian p'ul "downfall," Lithuanian puola "to fall," Old Prussian aupallai "finds," literally "falls upon").

Meaning "come suddenly to the ground" is from late Old English. Of darkness, night, from c. 1600; of land sloping from 1570s; of prices from 1570s. Of empires, governments, etc., from c. 1200. Of the face or countenance from late 14c. Meaning "to be reduced" (as temperature) is from 1650s. Meaning "die in battle" is from 1570s. Meaning "to pass casually (into some condition)" is from early 13c.

To fall in "take place or position" is from 1751. To fall in love is attested from 1520s; to fall asleep is late 14c. To fall down is early 13c. (a-dun follon); to fall behind is from 1856. Fall through "fail, come to nothing" is from 1781. To fall for something is from 1903.

To fall out is by mid-13c. in a literal sense; military use is from 1832. Meaning "have a disagreement, begin to quarrel" is attested from 1560s (to fall out with "quarrel with" is from late 15c.).
fall (n.): c. 1200, "a falling to the ground; a dropping from a height, a descent from a higher to a lower position (as by gravity); a collapsing of a building," from the source of fall (n.). (Old English noun fealle meant "snare, trap.") Meaning "a sinking down, subsidence" Of the coming of night from 1650s. Meaning "downward direction of a surface" is from 1560s, of a value from 1550s. Theological sense, "a succumbing to sin or temptation" (especially of Adam and Eve) is from early 13c.

Sense of "autumn" (now only in U.S. but formerly common in England) is by 1660s, short for fall of the leaf (1540s). Meaning "cascade, waterfall" is from 1570s (often plural, falls, when the descent is in stages; fall of water is attested from mid-15c.). Wrestling sense is from 1550s. Of a city under siege, etc., 1580s. Fall guy is from 1906.
fallacious (adj.): c. 1500, from fallacy (Latin fallacia) + -ous. Related: Fallaciously; fallaciousness.
fallacy (n.): late 15c., "deception, false statement," from Latin fallacia "deception, deceit, trick, artifice," noun of quality from fallax (genitive fallacis) "deceptive," from fallere "deceive" (see fail (v.)). Specific sense in logic, "false syllogism, invalid argumentation," dates from 1550s. An earlier form was fallace (c. 1300), from Old French fallace.
fallback: also fall-back, as a noun, "a reserve," 1851, from verbal phrase, from fall (v.) + back (adv.), which is attested in the sense of "retreat" from c. 1600. As an adjective, from 1767 as a type of chair; 1930 as "that may be used in an emergency."
fallen (adj.): c. 1400, past participle adjective from fall (v.). Used figuratively for "morally ruined" by 1620s, from the verb in the sense "yield to temptation" (especially in reference to women and chastity), attested from c. 1200. Meaning "those who have died" attested by 1765. Fallen angel is from 1680s; fallen woman by 1748.
fallibility (n.): 1630s, from Latin stem of fallible + -ity.
fallible (adj.): early 15c., from Medieval Latin fallibilis "liable to err, deceitful," literally "that can be deceived," from Latin fallere "deceive" (see fail (v.)).
falling (adj.): present participle adjective from fall (v.). Falling star is from 1560s; falling off "decrease, declining" is from c. 1600. Falling evil "epilepsy" is from early 13c.
Fallopian (adj.): 1706 in reference to the Fallopian tubes, from Latinized form of the name of Gabriello Fallopio (1523-1562), Italian anatomist who first described them.
fallout (n.): also fall-out, "radioactive particles," 1950, from fall (v.) + out (adv.).
fallow (n.): c. 1300, from Old English fealh "fallow land," from Proto-Germanic *falgo (source also of Old High German felga "harrow," German Felge "plowed-up fallow land," East Frisian falge "fallow," falgen "to break up ground"), perhaps from a derivation of PIE root *pel- (3) "to turn, fold." Assimilated since Old English to fallow (adj.), according to OED probably because of the color of plowed earth. Originally "plowed land," then "land plowed but not planted" (1520s). As an adjective, from late 14c.
fallow (adj.): "pale yellow, brownish yellow," Old English fealu "reddish yellow, yellowish-brown, tawny, dusk-colored" (of flame, birds' feet, a horse, withered grass or leaves, waters, roads), from Proto-Germanic *falwa- (source also of Old Saxon falu, Old Norse fölr, Middle Dutch valu, Dutch vaal, Old High German falo, German falb), from PIE *pal-wo- "dark-colored, gray" (source also of Old Church Slavonic plavu, Lithuanian palvas "sallow;" Greek polios "gray" (of hair, wolves, waves), Sanskrit palitah, Welsh llwyd "gray;" Latin pallere "to be pale"), suffixed form of root *pel- (2) "pale" (see pallor). It also forms the root of words for "pigeon" in Greek (peleia), Latin (palumbes), and Old Prussian (poalis). Related: Fallow-deer.
false (adj.): late Old English, "intentionally untrue, lying," of religion, "not of the true faith, not in accord with Christian doctrines," from Old French fals, faus "false, fake; incorrect, mistaken; treacherous, deceitful" (12c., Modern French faux), from Latin falsus "deceptive, feigned, deceitful, pretend," also "deceived, erroneous, mistaken," past participle of fallere "deceive, disappoint," which is of uncertain origin (see fail (v.)).

Adopted into other Germanic languages (cognates: German falsch, Dutch valsch, Old Frisian falsk, Danish falsk), though English is the only one in which the active sense of "deceitful" (a secondary sense in Latin) has predominated. From c. 1200 as "deceitful, disloyal, treacherous; not genuine;" from early 14c. as "contrary to fact or reason, erroneous, wrong." False alarm recorded from 1570s. False step (1700) translates French faux pas. To bear false witness is attested from mid-13c.
falsehood (n.): c. 1300, falshede, "deceitfulness," also "a lie; that which is false," from false + -hood. Formed on the same pattern are Old Frisian falschede, Dutch valschheid, German Falschheit, Swedish falskhet. Former noun forms in English, now extinct, included falsage "wrongdoing" (late 15c.), falsdom "deceitfulness, treachery; a lie" (c. 1300), fals-lek "falsehood" (early 14c.), falsshipe "deceitfulness, dishonesty" (c. 1200).
falsely (adv.): c. 1200, "with intent to deceive, deceitfully," from false + -ly (2). From c. 1300 as "wrongly; untruthfully;" early 14c. as "incorrectly."