Online Etymology Dictionary

guide (n.): mid-14c., "one who shows the way," from Old French guide, 14c., verbal noun from guider (see guide (v.)). In book titles from 1610s; meaning "book of information on local sites" is from 1759. In 18c. France, a "for Dummies" or "Idiot's Guide to" book would have been a guid' âne, literally "guide-ass." Guide-dog for the blind is from 1932.
guide-post (n.): also guidepost, 1761, from guide (v.) + post (n.1). Placed at a fork or intersection, with signs to guide travelers on their way.
guideline (n.): 1785, "line marked on a surface before cutting," from guide + line (n.). Meaning "rope for steering a hot-air balloon" is from 1846. In figurative use by 1948. Related: Guidelines.
Guido: masc. proper name, Italian, literally "leader," of Germanic origin (see guide (v.)). As a type of gaudy machoism often associated with Italian-Americans, 1980s, teen slang, from the name of character in Hollywood film "Risky Business" (1983).
guidon (n.): "small flag," originally one borne by a military unit to direct movements, 1540s, from Middle French guidon (16c.), from Italian guidone "battle standard," from guidare "to direct, guide," from Old Provençal guidar "to guide," from Proto-Germanic *witanan "to look after, guard" (see guide (v.)).
Guidonian (adj.): 1721, in reference to the system of musical notation devised by Guido d'Arezzo, who lived early 11c.
guild (n.): also gild, early 13c., yilde (spelling later influenced by Old Norse gildi "guild, brotherhood"), a semantic fusion of Old English gegield "guild, brotherhood," and gield "service, offering; payment, tribute; compensation," from Proto-Germanic *geldjam "payment, contribution" (source also of Old Frisian geld "money," Old Saxon geld "payment, sacrifice, reward," Old High German gelt "payment, tribute;" see yield (v.)).

The connecting sense is of a contribution or payment to join a protective or trade society. But some look to the alternative prehistoric sense of "sacrifice," as if in worship, and see the word as meaning a combination for religious purposes, either Christian or pagan. The Anglo-Saxon guilds had a strong religious component; they were burial societies that paid for Masses for the souls of deceased members as well as paying fines in cases of justified crime. Continental guilds of merchants, incorporated in each town or city and holding exclusive rights of doing business there, arrived after the Conquest. In many cases they became the governing body of a town (compare Guildhall, which came to be the London city hall). Trade guilds arose 14c., as craftsmen united to protect their common interest.
guilder (n.): Dutch gold coin, late 15c., probably from a mispronunciation of Middle Dutch gulden, literally "golden," in gulden (florijn) or some similar name for a golden coin (see golden).
guile (n.): mid-12c., from Old French guile "deceit, wile, fraud, ruse, trickery," probably from Frankish *wigila "trick, ruse" or a related Germanic source, from Proto-Germanic *wih-l- (source also of Old Frisian wigila "sorcery, witchcraft," Old English wig "idol," Gothic weihs "holy," German weihen "consecrate"), from PIE root *weik- (2) "consecrated, holy."
guileful (adj.): c. 1300, from guile + -ful. Nowadays only in poems and dictionaries. Related: Guilefully; guilefulness.
guileless (adj.): 1710, from guile + -less. Related: Guilelessly; guilelessness.
guillotine (n.): "The name of the machine in which the axe descends in grooves from a considerable height so that the stroke is certain and the head instantly severed from the body." ["Universal Magazine of Knowledge and Pleasure," January 1793], 1791, from French guillotine, named in recognition of French physician Joseph Guillotin (1738-1814), who as deputy to the National Assembly (1789) proposed, for humanitarian and efficiency reasons, that capital punishment be carried out by beheading quickly and cleanly on a machine, which was built in 1791 and first used the next year. Similar devices were used in the Middle Ages. The verb is first attested 1794. Related: Guillotined; guillotining.
guilt (n.): Old English gylt "crime, sin, moral defect, failure of duty," of unknown origin, though some suspect a connection to Old English gieldan "to pay for, debt," but OED editors find this "inadmissible phonologically." The -u- is an unetymological insertion. In law, "That state of a moral agent which results from his commission of a crime or an offense wilfully or by consent" [Century Dictionary], from early 14c. Then use for "sense of guilt," considered erroneous by purists, is first recorded 1680s. Guilt by association recorded by 1919.
guilt (v.): "to influence someone by appealing to his sense of guiltiness," by 1995, from guilt (n.). Related: Guilted; guilting. Old English also had a verbal form, gyltan (Middle English gilt), but it was intransitive and meant "to commit an offense, act criminally."
guiltiness (n.): late 14c., from guilty + -ness.
guiltless (adj.): late Old English gyltleas; see guilt (n.) + -less. Related: Guiltlessly; guiltlessness.
guilty (adj.): Old English gyltig "offending, delinquent, criminal," from gylt (see guilt (n.)). In law, "that has committed some specified offense," late 13c. Of conscience, feelings, etc., 1590s. Meaning "person who is guilty" is from 1540s. To plead not guilty is from 15c.; to plead guilty is 19c., though, as OED notes, "Guilty is technically not a plea, but a confession." Related: Guiltily; guiltiness.
guinea (n.): former British coin, 1660s, from Guinea, because the coins were first minted for British trade with Guinea (but soon in domestic use) and with gold from Africa. The original guinea was in use from 1663 to 1813.
Guinea: region along the west coast of Africa, presumably from an African word (perhaps Tuareg aginaw "black people"). As a derogatory term for "an Italian" (1896) it is from Guinea Negro (1740s) "black person, person of mixed ancestry;" applied to Italians probably because of their dark complexions relative to northern Europeans, and after 1911 it was occasionally applied to Hispanics and Pacific Islanders as well. New Guinea was so named 1546 by Spanish explorer Inigo Ortiz de Retes in reference to the natives' dark skin and tightly curled hair. The Guinea hen (1570s) is a domestic fowl imported from there. Related: Guinean.
guinea pig (n.): rodent native to South America, 1660s. It does not come from Guinea and has nothing to do with the pig. Perhaps so called either because it was brought back to Britain aboard Guinea-men, ships that plied the triangle trade between England, Guinea, and South America [Barnhart, Klein], or from its resemblance to the young of the Guinea-hog "river pig" [OED], or from confusion of Guinea with the South American region of Guyana (but OED is against this). Pig probably for its grunting noises. In the extended sense of "one subjected to an experiment" it is first recorded 1920, because they were commonly used in medical experiments (by 1865).
Guinevere: fem. proper name, from Welsh Gwenhwyvar, literally "white-cheeked."
Guinness: Irish brewery, founded 1759 by Arthur Guinness (1725-1803) in Dublin.
guise (n.): late 13c., "style or fashion of attire," from Old French guise "manner, fashion, way," from Frankish *wisa or some similar Germanic source, from Proto-Germanic *wison "appearance, form, manner," from *wissaz (source also of Old High German wisa "manner, wise"), from PIE root *weid- "to see" (see vision). Sense of "assumed appearance" is from 1660s, from earlier meaning "mask, disguise" (c. 1500).
guiser (n.): "masquerader, mummer, one who goes from house to house, whimsically disguised, and making diversion with songs and antics, usually at Christmas," late 15c., agent noun from guise.
guitar (n.): lute-like musical instrument, 1620s, from French guitare, which was altered by Spanish and Provençal forms from Old French guiterre, earlier guiterne, from Latin cithara, from Greek kithara "cithara," a triangular seven-stringed musical instrument related to the lyre, perhaps from Persian sihtar (see sitar). The name reached English several times, including giterne (early 14c., from Old French), in reference to various stringed, guitar-like instruments; the modern word is also directly from Spanish guitarra (14c.), which ultimately is from the Greek. The Arabic word is perhaps from Spanish or Greek, though often the relationship is said to be the reverse. The modern guitar is one of a large class of instruments used in all countries and ages but particularly popular in Spain and periodically so in France and England. Other 17c, forms of the word in English include guittara, guitarra, gittar, and guitarre. Compare zither, gittern.
guitarist (n.): 1770, from guitar + -ist.
Gujarati: from Gujarat, state in western India, Hindi, from Sanskrit Gurjara.
gulag (n.): system of prisons and labor camps, especially for political detainees, in the former Soviet Union; rough acronym from Russian Glavnoe upravlenie ispravitel'no-trudovykh lagerei "Chief Administration of Corrective Labor Camps," set up in 1931.
gulch (n.): "deep ravine," 1832, perhaps from obsolete or dialectal verb gulsh "sink in" (of land), "gush out" (of water), from Middle English gulchen "to gush forth; to drink greedily" (c. 1200). Compare gulche-cuppe "a greedy drinker" (mid-13c.). "There appears to be no etymological connection with gully" [Century Dictionary].
gules (adj.): "red," in heraldic descriptions, c. 1300, from Old French goules "neckpiece of (red) fur," plural of gole, guele "throat," from Latin gula "throat" (see gullet). Or perhaps the reference is to the red open mouth of the heraldic lion. Derivation from Persian gul "a rose" is "a poetical fancy" [Century Dictionary].
gulf (n.): late 14c., "profound depth," from Old French golf "a gulf, whirlpool," from Italian golfo "a gulf, a bay," from Late Latin colfos, from Greek kolpos "bay, gulf of the sea," earlier "trough between waves, fold of a loose garment," originally "bosom," the common notion being "curved shape." This is from PIE *kwelp- "to arch, to vault" (compare Old English hwealf, a-hwielfan "to overwhelm"). Latin sinus underwent the same development, being used first for "bosom," later for "gulf" (and in Medieval Latin, "hollow curve or cavity in the body"). The geographic sense "large tract of water extending into the land" (larger than a bay, smaller than a sea, but the distinction is not exact and not always observed) is in English from c. 1400, replacing Old English sæ-earm. Figurative sense of "a wide interval" is from 1550s. The U.S. Gulf States so called from 1836. The Gulf Stream (1775) takes its name from the Gulf of Mexico.
gull (n.1): shore bird, early 15c. (in a cook book), probably from Brythonic Celtic; compare Welsh gwylan "gull," Cornish guilan, Breton goelann; all from Old Celtic *voilenno-. Replaced Old English mæw (see mew (n.1)).
gull (n.2): cant term for "dupe, sucker, credulous person," 1590s, of uncertain origin. Perhaps from verb meaning "to dupe, cheat" (see gull (v.)). Or it is perhaps from (or influenced by) the bird name (see gull (n.1)); in either case with a sense of "someone who will swallow anything thrown at him." Another possibility is Middle English gull, goll "newly hatched bird" (late 14c.), which is perhaps from Old Norse golr "yellow," from the hue of its down.
gull (v.): "to dupe, cheat, mislead by deception," 1540s, earlier "to swallow" (1520s), ultimately from gull "throat, gullet" (early 15c.); see gullet. Related: Gulled; gulling.
Gullah: "of or pertaining to blacks on the sea-islands of Georgia and South Carolina," 1739 (first attested as a male slave's proper name), of uncertain origin. Early 19c. folk etymology made it a shortening of Angola (homeland of many slaves) or traced it to a West African tribal group called the Golas.
gullet (n.): "passage from the mouth of an animal to the stomach," c. 1300 (as a surname), from Old French golet "neck (of a bottle); gutter; bay, creek," diminutive of gole "throat, neck" (Modern French gueule), from Latin gula "throat," also "appetite," from PIE root *gwele- (3) "to swallow" (source also of Latin gluttire "to gulp down, devour," glutto "a glutton;" Old English ceole "throat;" Old Church Slavonic glutu "gullet," Russian glot "draught, gulp;" Old Irish gelim "I devour").
gullibility (n.): 1782, earlier cullibility (1728), probably from gull (n.2) "dupe, sucker" + -ability.
gullible (adj.): 1821, apparently a back-formation from gullibility. Spelling gullable is attested from 1818.
Gulliver: male proper name, from Old French goulafre "glutton," a very common name, found as a surname in Domesday Book (William Gulafra).
gully (n.): "channel in earth made by running water," 1650s, possibly a variant of Middle English golet "water channel" (see gullet). Gully-washer, American English colloquial for "heavy rainstorm," attested by 1887.
gulp (v.): late 14c., a native coinage or else from Flemish gulpe or Dutch gulpen "to gush, pour forth, guzzle, swallow," in any case possibly of imitative origin (compare Swedish dialectal glapa "to gulp down"). Related: Gulped; gulping.
gulp (n.): 1560s, from gulp (v.), or else from Flemish gulpe, Dutch gulp "stream of water, large draught."
gum (n.1): c. 1300, "resin from dried sap of plants," from Old French gome "(medicinal) gum, resin," from Late Latin gumma, from Latin gummi, from Greek kommi "gum," from Egyptian kemai. As the name of a hardened, sweetened gelatine mixture as a candy, 1827. As a shortened form of chewing gum, first attested 1842 in American English. The gum tree (1670s) was so called for the resin it exudes. Latin gummi also is the source of German Gummi (13c.).
gum (n.2): "soft tissues of the mouth," Old English goma "palate, side of the mouth" (single or plural), from a Germanic source represented by Old Norse gomi "palate," Old High German goumo; related to Lithuanian gomurys "palate," and perhaps from PIE root *gheu- "to yawn" (source also of Old English ginian "to yawn;" see yawn (v.)).
gum (v.1): early 14c., gommen, "treat with (medicinal or aromatic) gums," from gum (n.1). In the transferred or figurative sense of "spoil, ruin" (usually with up), as if by some gummy substance, it is first recorded 1901, probably from the notion of machinery becoming clogged. Related: Gummed; gumming.
gum (v.2): of infants, toothless adults, etc., "to chew or gnaw (something) with the gums," by 1907, from gum (n.2). Related: Gummed; gumming.
gum-drop (n.): also gumdrop, type of confection, 1856, from gum (n.1) + drop (n.).
gumbo (n.): soup thickened with okra, 1805, from Louisiana French, probably ultimately from Central Bantu dialect (compare Mbundu ngombo "okra"). Also used for "the creole patois of Louisiana" (1838).
gummy (adj.): "gum-like, sticky," late 14c., from gum (n.1) + -y (2). Related: Gumminess.
gump (n.): "dolt, numskull, foolish person," 1825, "a term most generally applied to a female" [Jamieson]; meaning "chicken" is from 1914, U.S. thieves' slang.