Online Etymology Dictionary

moonlight (v.): "hold a second job, especially at night," 1957 (implied in moonlighting), from moonlighter (1954), from the notion of working by the light of the moon; see moonlight (n.). Related: Moonlighting. Earlier the word had been used to mean "commit crimes at night" (1882).
mope (v.): 1560s, "to move and act unconsciously;" 1580s, "to be listless and apathetic," the sound of the word perhaps somehow suggestive of low feelings (compare Low German mopen "to sulk," Dutch moppen "to grumble, to grouse," Danish maabe, dialectal Swedish mopa "to mope"). Related: Moped; moping; mopey; mopish.
bungle (v.): 1520s, origin obscure. OED suggests imitative; perhaps a mix of boggle and bumble, or more likely from a Scandinavian word akin to Swedish bangla "to work ineffectually," Old Swedish bunga "to strike" (related to German Bengel "cudgel," also "rude fellow"). Related: Bungled; bungling.
burd (n.): poetic word for "woman, lady" in old ballads; later "young lady, maiden;" c. 1200, perhaps from Old English byrde "wealthy, well-born." Or a metathesis of bryd "bride." The masculine equivalent was berne.
butternut (n.): also butter-nut, 1753, nut of the white walnut, a North American tree; transferred to the tree itself from 1783. The nut's color was a brownish-gray, hence the word was used (1861) to describe the warm gray color of the Southern army uniforms in the American Civil War.
-aster: word-forming element expressing incomplete resemblance (such as poetaster), usually diminutive and deprecatory, from Latin -aster, from a suffix forming nouns from verbs ending in Greek -azein; in later Latin generalized as a pejorative suffix, as in patraster "he who plays the father."
astute (adj.): 1610s, from Latin astutus "crafty, wary, shrewd; sagacious, expert," from astus "cunning, cleverness, adroitness," which is of uncertain origin, perhaps from Greek asty "town," a word borrowed into Latin and with an overtone of "city sophistication" (compare asteism). Related: Astutely; astuteness.
bud (n.): late 14c., budde, origin unknown, perhaps from Old French boter "push forward, thrust," itself a Germanic word (compare Dutch bot "bud," Old Saxon budil "bag, purse," German Beutel), or perhaps from Old English budd "beetle."
Bufo (n.): toad genus, from Latin bufo "a toad," an Osco-Umbrian loan-word, perhaps from PIE *gwebh-, a root denoting sliminess and also forming words for "frog" (source also of Old Prussian gabawo "toad," Old Church Slavonic žaba "frog," Middle Low German kwappe "tadpole," German Quappe).
poseur (n.): "one who practices affected attitudes," 1866, from French poseur, from verb poser "affect an attitude or pose," from Old French poser "to put, place, set" (see pose (v.1)). The word is English poser in French garb, and thus could itself be considered an affectation.
transmutation (n.): late 14c., from Old French transmutacion "transformation, change, metamorphosis" (12c.), from Late Latin transmutationem (nominative transmutatio) "a change, shift," noun of action from Latin transmutare "change from one condition to another," from trans- "thoroughly" (see trans-) + mutare "to change" (see mutable). A word from alchemy.
plethora (n.): 1540s, a medical word for "excess of body fluid," from Late Latin plethora, from Greek plethore "fullness," from plethein "be full" (see pleio-). Figurative meaning "too-muchness, overfullness in any respect" is first recorded 1700. Related: Plethoric.
artisan (n.): 1530s, from Italian artesano, from Vulgar Latin artitianus, from Latin artitus, past participle of artire "to instruct in the arts," from ars (genitive artis) "art" (see art (n.)). Barnhart reports Middle French artisan, often listed as the direct source of the English word, is attested too late to be so.
bravado (n.): 1580s, from French bravade "bragging, boasting," from Italian bravata "bragging, boasting" (16c.), from bravare "brag, boast, be defiant," from bravo (see brave (adj.)). The English word was influenced in form by Spanish words ending in -ado.
breath (n.): Old English bræð "odor, scent, stink, exhalation, vapor" (Old English word for "air exhaled from the lungs" was æðm), from Proto-Germanic *bræthaz "smell, exhalation" (source also of Old High German bradam, German Brodem "breath, steam"), from PIE root *gwhre- "to breathe, smell."
brisket (n.): mid-14c., brusket, perhaps from Old French bruschet, with identical sense of the English word, or from Old Norse brjosk "gristle, cartilage" (related to brjost "breast") or Danish bryske or Middle High German brusche "lump, swelling;" from PIE *bhreus- "to swell, sprout" (see breast (n.)).
rue (n.1): perennial evergreen shrub, late 14c., from Old French rue (13c.), earlier rude, from Latin ruta "rue," probably from Greek rhyte, of uncertain etymology, originally a Peloponnesian word. The bitter taste of its leaves led to many punning allusions to rue (n.2.).
Ruthenian (adj.): 1850, of or pertaining to the Ukrainian people (earlier Ruthene, 1540s), from Medieval Latin Rutheni "the Little Russians," a derivative of Russi (see Russia). For consonant change, compare Medieval Latin Prut(h)eni, from Prussi "Prussians." Another word in the same sense was Russniak.
brumal (adj.): "belonging to winter," 1510s, from Latin brumalis, from bruma "winter" (see brume). The Latin word also is the ultimate source of Brumaire, second month (Oct. 22-Nov. 20) in calendar of the French Republic, literally "the foggy month," coined 1793 by Fabre d'Eglantine from French brume "fog" (see brume).
brunch: 1896, British student slang merger of breakfast and lunch.
To be fashionable nowadays we must 'brunch'. Truly an excellent portmanteau word, introduced, by the way, last year, by Mr. Guy Beringer, in the now defunct Hunter's Weekly, and indicating a combined breakfast and lunch. ["Punch," Aug. 1, 1896]
brute (adj.): early 15c., "of or belonging to animals," from Middle French brut "coarse, brutal, raw, crude," from Latin brutus "heavy, dull, stupid," an Oscan word, from PIE root *gwere- (2) "heavy" (see grave (adj.)). Before reaching English the meaning expanded to "of the lower animals." Used of human beings from 1530s.
buckwheat (n.): 1540s, from Middle Dutch boecweite "beech wheat" (compare Danish boghvede, Swedish bovete, German Buchweizen), so called from resemblance between grains and seed of beech trees. Possibly a native formation on the same model as the Dutch word, from a dialectal form of beech. See beech + wheat.
con-: word-forming element meaning "together, with," sometimes merely intensive; the form of com- used in Latin before consonants except -b-, -p-, -l-, -m-, or -r-. In native English formations (such as costar), co- tends to be used where Latin would use con-.
condense (v.): early 15c., from Middle French condenser (14c.) or directly from Latin condensare "to make dense," from com-, intensive prefix (see com-), + densare "make thick," from densus "dense, thick, crowded," a word used of crowds, darkness, clouds, etc. (see dense).
architect (n.): 1550s, from Middle French architecte, from Latin architectus, from Greek arkhitekton "master builder, director of works," from arkhi- "chief" (see archon) + tekton "builder, carpenter" (see texture). An Old English word for it was heahcræftiga "high-crafter."
armada (n.): "fleet of warships," 1530s (erroneously, as armado), from Spanish armada "an armed force," from Medieval Latin armata (see army). Especially of the "Invincible Armada" of Philip II of Spain (1588). Current form of the word is from 1590s. The Spanish Armada of 1588 was so called by 1613; Invincible Armada attested by 1632.
armoire (n.): 1570s, from French armoire, from Old French armarie (12c.) "cupboard, bookcase, reliquary," from Latin armarium "closet, chest, place for implements or tools," from arma "gear, tools, arms" (see arm (n.2)). Before being reborrowed from French, the word earlier was in English as ambry (late 14c.).
arroyo (n.): "watercourse, dry streambed," 1845, a California word, from American Spanish, in Spanish, "rivulet, small stream," from Latin arrugia "shaft or pit in a gold mine," apparently a compound of ad- "to" (see ad-) + ruga "a wrinkle" (see rough (adj.)).
modernism (n.): 1737, "deviation from the ancient and classical manner" [Johnson, who calls it "a word invented by Swift"], from modern + -ism. From 1830 as "modern ways and styles." Used in theology since 1901. As a movement in the arts (away from classical or traditional modes), from 1929.
Missouri: originally a name for a group of native peoples among Chiwere (Siouan) tribes, from an Algonquian word recorded c. 1700, literally "people of the big canoes." The expression I'm from Missouri, you'll have to show me is attested from at least c. 1880. Related: Missourian.
pistachio (n.): 1590s, from Italian pistacchio, from Latin pistacium "pistachio nut," from Greek pistakion "pistachio nut," from pistake "pistachio tree," from Persian pistah "pistachio." Borrowed earlier (1530s) as pystace, from Old French form pistace (13c.), which also is from the Italian word.
tyrant (n.): c. 1300, "absolute ruler," especially one without legal right; "cruel, oppressive ruler," from Old French tiran, tyrant (12c.), from Latin tyrannus "lord, master, monarch, despot," especially "arbitrary ruler, cruel governor, autocrat" (source also of Spanish tirano, Italian tiranno), from Greek tyrannos "lord, master, sovereign, absolute ruler unlimited by law or constitution," a loan-word from a language of Asia Minor (probably Lydian); Klein compares Etruscan Turan "mistress, lady" (surname of Venus).
In the exact sense, a tyrant is an individual who arrogates to himself the royal authority without having a right to it. This is how the Greeks understood the word 'tyrant': they applied it indifferently to good and bad princes whose authority was not legitimate. [Rousseau, "The Social Contract"]
Originally in Greek the word was not applied to old hereditary sovereignties (basileiai) and despotic kings, but it was used of usurpers, even when popular, moderate, and just (such as Cypselus of Corinth), however it soon became a word of reproach in the usual modern sense. The spelling with -t arose in Old French by analogy with present participle endings in -ant. Fem. form tyranness is recorded from 1590 (Spenser); Medieval Latin had tyrannissa (late 14c.).
attack (v.): c. 1600, from French attaquer (16c.), from Florentine Italian attaccare (battaglia) "join (battle)," thus the word is a doublet of attach, which was used 15c.-17c. also in the sense now reserved to attack. Related: Attacked; attacking.
mum (n.2): pet word for "mother," 1823, short for mummy (see mamma). In British sociology, used from 1957 in reference to "the working class mother as an influence in the lives of her children." Also sometimes a vulgar corruption of madam.
stannic (adj.): "containing tin," 1790, from Modern Latin stannum, from Late Latin stannum "tin" (earlier "alloy of silver and lead"), a scribal alteration of Latin stagnum, probably from a Celtic source (compare Irish stan "tin," Cornish and Breton sten, Welsh ystaen). The Latin word is the source of Italian stagno, French étain, Spanish estaño "tin."
-some (1): word-forming element used in making adjectives from nouns or adjectives (and sometimes verbs) and meaning "tending to; causing; to a considerable degree," from Old English -sum, identical with som (see some). Cognate with Old Frisian -sum, German -sam, Old Norse -samr; also related to same.
preliminary (adj.): 1660s, from French préliminaire and directly from Medieval Latin praeliminaris, from Latin prae- "before" (see pre-) + limen (genitive liminis) "threshold" (see limit (n.)). A word that arose in reference to negotiations to end the Thirty Years' War. Earliest attested form in English is preliminaries (n.), 1650s.
aunt (n.): c. 1300, from Anglo-French aunte, Old French ante (Modern French tante, from a 13c. variant), from Latin amita "paternal aunt" diminutive of *amma a baby-talk word for "mother" (source also of Greek amma "mother," Old Norse amma "grandmother," Middle Irish ammait "old hag," Hebrew em, Arabic umm "mother").

Extended senses include "an old woman, a gossip" (1580s); "a procuress" (1670s); and "any benevolent woman," in American English, where auntie was recorded since c. 1790 as "a term often used in accosting elderly women." The French word also has become the word for "aunt" in Dutch, German (Tante), and Danish. Swedish has retained the original Germanic (and Indo-European) custom of distinguishing aunts by separate terms derived from "father's sister" (faster) and "mother's sister" (moster). The Old English equivalents were faðu and modrige. In Latin, too, the formal word for "aunt on mother's side" was matertera. Some languages have a separate term for aunts-in-law as opposed to blood relations.
avow (v.): early 13c., from Anglo-French avouer, Old French avoer "acknowledge, accept, recognize," especially as a protector (Modern French avouer), from Latin advocare (see advocate). A synonym of avouch (q.v.), which tends to contain the more technical, legal aspect of the word. Related: Avowed; avowing.
coulee (n.): "deep ravine, seasonally flooded," 1804, a North American word, originally in areas explored by French trappers, from French coulée "flow" (17c.), from fem. past participle of couler "to flow," from Latin colare "to filter, strain" (see colander).
snafu (n.): 1941, U.S. military slang, acronym for situation normal, all fucked up, "an expression conveying the common soldier's laconic acceptance of the disorder of war and the ineptitude of his superiors" ["Oxford English Dictionary"]. As an adjective from 1942. In public explanations the word typically was euphemised to fouled.
snip (n.): 1550s, "small piece of cut-out cloth," probably from Dutch or Low German snippen "to snip, shred," of imitative origin. Meaning "cut made by scissors" is from 1590s. As a nickname or cant word for a tailor, 1590s. Snip-snap-snorum, the card game, is 1755, from Low German.
socio-: word-forming element meaning "social, of society; social and," also "having to do with sociology," from combining form of Latin socius "companion, ally, associate, fellow, sharer" (see social (adj.)). Common in compounds since c. 1880.
soliloquy (n.): 1610s, from Late Latin soliloquium "a talking to oneself," from Latin solus "alone" (see sole (adj.)) + loqui "speak" (see locution). Also used in translation of Latin "Liber Soliloquiorum," a treatise by Augustine, who is said to have coined the word, on analogy of Greek monologia (see monologue). Related: Soliloquent.
solon (n.): "legislator," 1620s, from Greek Solon, name of early lawgiver of Athens, one of the seven sages. Often, especially in U.S., applied (with perhaps a whiff of sarcasm) by journalists to Congressmen, township supervisors, etc. It also is a useful short headline word.
speckle (v.): mid-15c. (implied in speckled), probably related to Old English specca "small spot, speck" (see speck) or from a related Middle Dutch or Middle High German word. Related: Speckled; speckling. The noun is first attested mid-15c.
simulacrum (n.): 1590s, from Latin simulacrum "likeness, image, form, representation, portrait," dissimilated from *simulaclom, from simulare "to make like, imitate, copy, represent" (see simulation). The word was borrowed earlier as semulacre (late 14c.), via Old French simulacre.
sulfa: 1942, short name for the group of drugs derived from sulfanilamide ("amide of sulfanilic acid," 1937, which is so called because it is a sulphonic derivative of the dye-stuff aniline), and shortened from that word. The usual British English spelling is sulpha.
ther-: often thero-, word-forming element meaning "beast," from comb. form of Greek ther "wild beast, beast of prey," from PIE *ghwer- "wild beast" (source also of Latin ferus "wild," ferox "fierce;" see fierce). Also therio-, from Greek therion.
thermodynamics (n.): theory of relationship between heat and mechanical energy, 1854, from thermodynamic (adj.); also see -ics. "The consideration of moving forces, though suggested by the form of the word, does not enter into the subject to any considerable extent" [Century Dictionary].