Online Etymology Dictionary

jillion (n.): by 1939, arbitrary coinage, modeled on million, etc.
jilt (v.): "to deceive (especially after holding out hopes), discard after encouraging," 1670s; earlier "to cheat, trick" (1660s); of uncertain origin (see jilt (n.)). Related: Jilted; jilting.
jilt (n.): 1670s, "loose, unchaste woman; harlot;" also "woman who gives hope then dashes it;" probably a contraction of jillet, gillet, from Middle English gille "lass, wench," a familiar or contemptuous term for a woman or girl (mid-15c.), originally a shortened form of woman's name Gillian (see Jill).
Jim Crow: "black man," 1838, American English, originally the name of a black minstrel character in a popular song-and-dance act by T.D. Rice (1808-1860) that debuted 1828 and attained national popularity by 1832:
Wheel about, an' turn about, an' do jis so;
Eb'ry time I wheel about, I jump Jim Crow.
Where and how Rice got it, or wrote it, is a mystery. Even before that, crow (n.) had been a derogatory term for a black man. As an adjective from 1833, in reference to the song. Association with segregation dates from 1841, in reference to separate railroad cars for blacks in Massachusetts. Modern use as a type of racial discrimination is from 1943. Jim Crow also could be a reference to someone's change of (political) principles (1837, from the "jump" in the song) or reversible machinery (1875, "wheel about").
On his arrival in Boston, Mr. [Charles Lenox] R[emond] went to the Eastern rail-road depot, in order to visit his parents in Salem; but, instead of being allowed to ride with other passengers, he was compelled to take a seat in what is contemptuously called the "Jim Crow car," as though he were a leper or a wild animal! [Annual Report of the Massachusetts Anti-Slavery Society, 1842]
jim-dandy (n.): "remarkable person or thing," 1844, perhaps from an old song, "Dandy Jim of Caroline" (1840s).
jim-jam (n.): "knick-knack," 1640s, a reduplication of unknown origin.
Jiminy (interj.): exclamation of surprise, 1803, colloquial form of Gemini, a disguised oath, perhaps Jesu Domine "Jesus Lord." Extended form jiminy cricket is attested from 1848, according to OED, and suggests Jesus Christ (compare also Jiminy Christmas, 1890). It was in popular use in print from c. 1901 and taken into the Pinocchio fairy tale by Disney (1940) to answer to Italian Il Grillo Parlante "the talking cricket."
jimmies (n.): bits of candy as ice cream topping, by 1963, American English, of uncertain origin. Earlier it meant "delirium tremens" (1900) from earlier jim-jam (1885).
jimmy (n.): "burglar's crowbar," 1848, variant of jemmy, name for a type of crowbar much used by burglars, special use of Jemmy, familiar form of proper name James (compare the mechanical uses of jack (n.)).
jimmy (v.): "pry open with short leverage," 1893, from jimmy (n.). Related: Jimmied; jimmying.
jimson-weed (n.): also jimsonweed, 19c. American English corrupt shortening of Jamestown-weed (1680s), from Jamestown, Virginia colony, where it was discovered by Europeans (1676), when British soldiers mistook it for an edible plant and subsequently hallucinated for 11 days.
jingle (v.): "emit tinkling metallic sounds," late 14c., gingeln, of imitative origin (compare tinkle (v.), Dutch jengelen, German klingeln). "There does not appear any original association with jangle" [OED]. Transitive sense "cause to emit a jingling sound" is from c. 1500. Related: Jingled; jingling. Massinger has jingle-boy "a coin" (c. 1600). Jingle-bell is attested from 1871. Jingle-brains (1700) was slang for "a wild, thoughtless, rattling fellow" [Grose].
jingle (n.): "tinkling or clinging sound," such as made by small bells, 1590s, from jingle (v.). Meaning "something that jingles" is from 1610s, especially "metallic disc on a tambourine." Meaning "song in an advertisement" first attested 1930, from earlier sense of "catchy array of words in prose or verse" (1640s).
jingle-jangle (v.): 1630s, varied reduplication of jingle (v.).
jinglet (n.): "loose metal ball serving as the clapper of a sleigh-bell," 1875, diminutive of jingle (n.).
jingo (n.): "mindless, militaristic patriot," 1878, picked up from the refrain of a music hall song written by G.W. Hunt, and sung by "Gilbert H. MacDermott" (1845-1901), supporting aggressive British policy toward Russia at a time of international tension. ("We don't want to fight, But by Jingo! if we do, We've got the ships, we've got the men, We've got the money too.")
Hunt's patriotic song of 1878, with a swinging tune ... became at Macdermott's instigation the watchword of the popular supporters of England's bellicose policy. The "Daily News" on 11 March 1878 first dubbed the latter 'Jingoes' in derision .... ["Dictionary of National Biography," London, 1912]
As an asseveration, by jingo was in colloquial use from 1690s (high jingo is attested from 1660s), and jingo here is apparently yet another euphemism for Jesus (it translates French Par Dieu), influenced by conjurer's gibberish presto-jingo (attested from 1660s). The frequent suggestion that it somehow derives from Basque Jinkoa "god" is "not impossible" but is "as yet unsupported by evidence" [OED].
jingoism (n.): 1878, from jingo + -ism. Related: Jingoist; jingoistic.
jink (v.): 1715, "move nimbly; wheel or fling about in dancing," a Scottish word of unknown origin. It also came to mean "elude, dodge" (1774); "to trick, cheat" (1785). As a noun, "act of eluding" (1786). For high jinks, see hijinks, the date of which suggests this word is older than the record.
jinn (n.): 1680s, djen, from Arabic jinn. It is a collective plural, "demons, spirits, angels;" the proper singular is jinni, which appears in English occasionally as jinnee (1840) but more frequently as genie. Similarity to genius is accidental.
Jinny: also Ginny, fem. proper name, originally a diminutive of Jane, and like Jenny it also was used of machinery.
jinx (n.): 1911, American English, originally baseball slang; perhaps ultimately from jyng "a charm, a spell" (17c.), originally "wryneck" (also jynx), a bird used in witchcraft and divination, from Latin iynx "wryneck," from Greek iynx. Jynx was used in English as "a charm or spell" from 1690s.
Most mysterious of all in the psychics of baseball is the "jinx," that peculiar "hoodoo" which affects, at times, a man, at other times a whole team. Let a man begin to think that there is a "jinx" about, and he is done for for the time being. ["Technical World Magazine," 1911]
The verb is 1912 in American English, from the noun. Related: Jinxed; jinxing.
jirgah (n.): also jirga, Afghan council of elders, 1815, from Persian jarga "ring of men."
jism (n.): "seminal fluid, cum," 1899; earlier "energy, strength" (1842), of uncertain origin; see jazz (n.).
jitney (n.): "bus which carries passengers for a fare," 1915, short for jitney bus (1906), American English, from gitney (n.), said in a 1903 newspaper article to be a St. Louis slang for any small coin, especially "a nickel," (the buses' fare typically was a nickel), the coin name perhaps via New Orleans from French jeton "coin-sized metal disk, slug, counter" (see jetton).
"I'll give a nickel for a kiss,"
Said Cholly to a pretty miss.
"Skiddo," she cried, "you stingy cuss,"
"You're looking for a jitney buss."

["Jitney Jingle," 1915]
The origin and signification of the word was much discussed when the buses first appeared. Some reports say the slang word for "nickel" comes from the bus; most say the reverse, however there does not seem to be much record of jitney in a coin sense before the buses came along (a writer in "The Hub," August 1915, claims to have heard and used it as a small boy in San Francisco, and reported hearsay that "It has been in use there since the days of '49"). Most sources credit it to the U.S. West, especially California, though others trace it to "southern negroes, especially in Memphis" ["The Pacific," Feb. 7, 1915].
jitter (v.): "to move agitatedly," 1931, American English, of unknown origin; see jitters. Related: Jittered; jittering.
jitterbug (n.): popular type of fast swing dance, 1938, American English, from "Jitter Bug," title of a song recorded by Cab Calloway in 1934. Probably the literal sense is "one who has the jitters" (see jitters; for second element see bug (n.) in the slang "person obsessed with" sense). Another sense current about this time was "swing music enthusiast" (1937). As a verb from 1938.
jitters (n.): "extreme nervousness," 1925, American English, perhaps an alteration of dialectal chitter "tremble, shiver," from Middle English chittern "to twitter, chatter."
jittery (adj.): 1931, American English, from jitter + -y (2). Related: Jitteriness.
jive (v.1): the word appears in 1928 in American-English, meaning "to deceive playfully," also with noun sense "empty, misleading talk" and as the name of a style of fast, lively jazz and dance music;" from African-American vernacular and probably of African origin (compare Wolof jev, jeu "talk about someone absent, especially in a disparaging manner"). Related: Jived; jiving.
jive (v.2): "agree," 1943, apparently a mistake for jibe (v.), influenced by jive (v.1).
jive (adj.): "not acting right," 1969, African-American vernacular, from jive (n.). Extended form jive-ass (1964, adj.; 1969, n.) is defined in OED as "A word of fluid meaning and application," but generally disparaging.
jive (n.): "empty, misleading talk;" also a style of fast, lively jazz and dance music," 1928, American English, from jive (v.1). Used from 1938 for "New York City African-American slang."
jivey (adj.): a word popularized by, if not coined in, the song "Mairzy Doats," from jive (n.) + -y (2). As to sense, it has meant "jazzy, swinging," but also "phony, fake."
jo (n.): also joe, "sweetheart, darling," probably a Scottish form of joy (n.), which attested from 1520s as a term of endearment.
Joachim: masc. proper name; a Joachimite (1797) was a follower of Italian mystic Joachim of Floris (obit c. 1200) who preached the reign of the Holy Spirit on earth, with a new gospel, would begin in 1260.
Joan: fem. proper name, Middle English Joan, Jone, variants of Jean, Jane, from Medieval Latin Joanna, fem. of Late Latin Joannes (see John). Often 17c.-18c. used as a generic name for a female rustic, or with Darby as the characteristic names of an old, happily married couple (1735). Among U.S. births, a top 10 name for girls born between 1930 and 1937.
job (n.): "piece of work; something to be done," 1620s, from phrase jobbe of worke (1550s) "task, piece of work" (contrasted with continuous labor), a word of uncertain origin. Perhaps a variant of gobbe "mass, lump" (c. 1400; see gob) via sense of "a cart-load." Specific sense of "work done for pay" first recorded 1650s.
job. (1) A low mean lucrative busy affair. (2) Petty, piddling work; a piece of chance work. [Johnson's Dictionary]
Meaning "paid position of employment" is from 1858. Printers' slang sense "piece of work of a miscellaneous class" (posters, handbills, etc.) is from 1795, hence job-type (notably large or ornamental or of exceptional form), job-shop, etc. Job lot (1832) is from an obsolete sense of "cartload, lump," which might be a separate formation from gob.

The very broad general sense of "occurrence, business, state of things" is colloquial from c. 1700. In modern slang or colloquial use, "an example," especially a good one (of the thing indicated), 1927, "a term of wide application" [OED]. Thieves' slang sense of "theft, robbery, a planned crime" is from 1722. Slang meaning "specimen, thing, person" is from 1927. On the job "hard at work" is from 1882. Job security attested by 1932 (job insecurity by 1936); job description by 1920; job-sharing by 1972. Job-hunter is from 1928. The phrase job of work still appears as late as Trollope (1873).
Job: Biblical masc. proper name, name of an ancient patriarch whose story forms a book of the Old Testament, from Hebrew Iyyobh, which according to some scholars is literally "hated, persecuted," from ayyabh "he was hostile to," related to ebhah "enmity." Others say it means "the penitent one." Figurative of bad news, destitution, and patient endurance. Hence Job's comforter, of one who brings news of additional misfortune (1736).
job (v.): 1660s, "to buy and sell as a broker" (intransitive), from job (n.). Meaning "deal in public stocks on one's own account" is from 1721. Meaning "to cheat, betray" is from 1903; earlier "pervert pubic service to private advantage" (1732). Related: Jobbed; jobbing.
Jobation (n.): "a long, tedious scolding," 1680s, a jocular formation from Job, the patriarch, with a Latinate noun ending, "in allusion to the rebukes he received from his 'comforters'" [Century Dictionary]. A verb jobe is attested from 1660s.
jobbard (n.): "fool, stupid man," mid-15c., probably from Middle French jobard, from jobe "silly." Earlier jobet (c. 1300).
jobber (n.): "one who does odd jobs or chance work," 1706, agent noun from job (v.) in a sense of "to let out in separate portions," hence "to work for different contractors." Also jobster (1891). Earlier it meant "one who purchases and resells, a middleman" (1660s); "intriguer who works to his own advantage" (1739).
jobless (adj.): "out of work, unemployed," 1905, from job (n.) + -less. As a noun, "jobless person or persons," from 1909. Related: Joblessness.
Jocelin: masc. proper name with many variant forms, introduced in English by the Normans, from Old High German Gautelen, from Gauta, literally "Goth" (see Goth). French fem. form is Joceline.
Jocelyn: proper name, variant of Jocelin/Joceline.
jock (n.): 1952, short for jockstrap "supporter of the male genital organs," which also meant, in slang, "athletic male." Jock with the meaning "an athletic man" is from 1963, American English slang. A jockette (1948) originally was a female disk jockey, then a female jockey (1969), then an athletic female (1979).
Jock: c. 1500, variant of the masc. proper name Jack, the by-form of John. In Scotland and northern England it is the usual form. Since 1520s, like Jack, it has been used generically, as a common appellative of lads and servants, as the name of a typical man of the common folk, of a Scottish or North Country seaman, etc.
jockey (n.): "person who rides horses in races," 1660s, a specific use of the earlier sense "boy, fellow" (1520s), which is a special use of the Scottish proper name Jockey, a familiar or diminutive form of Jock. Jockey-boots are from 1680s; jockey-shorts "abbreviated underwear for men" is from 1935 (jockey-briefs from 1946).
jockey (v.): 1708, "trick, outwit, gain advantage," from jockey (n.) perhaps in its former secondary sense of "horse trader" (1680s) and reflecting their reputation. Meaning "to ride a horse in a race" is from 1767. Related: Jockeyed; jockeying.
jockstrap (n.): also jock-strap, "supporter of the male genital organs, used in sports," 1887, with strap (n.) + jock slang for "penis" c. 1650-c. 1850, probably one of the many colloquial uses of Jock (the northern and Scottish form of Jack), which was used generically for "common man" from c. 1500. Jockey-strap in the same sense is from 1890, with also an example from 1870 but the sense is uncertain.