Online Etymology Dictionary

off-site (adj.): 1956, from off (adv.) + site (n.).
off-stage (adj.): also offstage, 1915, from off (adv.) + stage (n.).
off-street (adj.): 1929, from off (adv.) + street.
off-white (n.): "white with a tinge of gray or yellow," 1927, from off (adv.) + white (n.).
offal (n.): late 14c., "waste parts, refuse," from off + fall (v.); the notion being that which "falls off" the butcher's block; perhaps a translation of Middle Dutch afval.
offence (n.): see offense.
offend (v.): early 14c., "to sin against (someone)," from Old French ofendre "transgress, antagonize," and directly from Latin offendere "to hit, strike against," figuratively "to stumble, commit a fault, displease, trespass against, provoke," from ob "against" (see ob-) + -fendere "to strike" (found only in compounds; see defend).

Meaning "to violate (a law), to make a moral false step, to commit a crime" is from late 14c. Meaning "to wound the feelings" is from late 14c. The literal sense of "to attack, assail" is attested from late 14c.; this has been lost in Modern English, but is preserved in offense and offensive. Related: Offended; offending.
offender (n.): mid-15c., agent noun from offend (v.). Earlier was offendour (early 15c.), from Anglo-French.
offense (n.): late 14c., "hurt, harm, injury, pain," from Old French ofense "offense, insult, wrong" (13c.) and directly from Latin offensa "an offense, injury, affront, crime," literally "a striking against," noun use of fem. past participle of offendere (see offend). Meaning "action of attacking" and "feeling of being hurt" are both first recorded c. 1400. Sense of "breach of the law, transgression" is first recorded late 14c. Sporting sense first recorded 1894.
offensive (adj.): "attacking" (1540s), "insulting" (1570s), both from Middle French offensif (16c.) and directly from Medieval Latin offensivus, from Latin offens-, past participle stem of offendere "offend" (see offend). Related: Offensively; offensiveness.
offensive (n.): "condition of attacking, aggressive action," 1720, from offensive (adj.).
offer (v.): Old English ofrian "to offer, show, exhibit, sacrifice, bring an oblation," from Latin offerre "to present, bestow, bring before" (in Late Latin "to present in worship"), from ob "to" (see ob-) + ferre "to bring, to carry" (see infer). The Latin word was borrowed elsewhere in Germanic: Old Frisian offria, Middle Dutch offeren, Old Norse offra. Non-religious sense reinforced by Old French offrir "to offer," from Latin offerre. Related: Offered; offering.
offer (n.): early 15c., from Old French ofre "act of offering; offer, proposition" (12c.), verbal noun from offrir (see offer (v.)). The native noun formation is offering.
offering (n.): late Old English offrung "the presenting of something to a deity; a thing so presented," verbal noun from offrian (see offer (v.)). Of presentations to a person from mid-15c.; to the public from 1834.
offertory (n.): "the part of a Mass at which offerings are made," late 14c., from Medieval Latin offertorium "place where offerings are brought," from Vulgar Latin offertus, corresponding to Latin oblatus, past participle of offerre (see offer (v.)). Meaning "part of a religious service" is first recorded 1530s; sense of "collection of money" is from 1862.
office (n.): mid-13c., "a post, an employment to which certain duties are attached," from Anglo-French and Old French ofice "place or function; divine service" (12c. in Old French) or directly from Latin officium "service, kindness, favor; official duty, function, business; ceremonial observance," (in Church Latin, "church service"), literally "work-doing," from ops (genitive opis) "power, might, abundance, means" (related to opus "work;" see opus) + stem of facere "do, perform" (see factitious). Meaning "place for conducting business" first recorded 1560s. Office hours attested from 1841.
officer (n.): early 14c., "one who holds an office" (originally a high office), from Old French oficier "officer, official" (early 14c.), from Medieval Latin officarius "an officer," from Latin officium "a service, a duty" (see office). The military sense is first recorded 1560s. Applied to petty officials of justice from 16c.; U.S. use in reference to policemen is from 1880s.
official (n.): early 14c., from Old French oficial "law officer; bishop's representative" (12c.) and directly from Late Latin officialis "attendant to a magistrate, public official," noun use of officialis (adj.) "of or belonging to duty, service, or office" (see official (adj.)). Meaning "person in charge of some public work or duty" first recorded 1550s.
official (adj.): late 14c., "performing a service; required by duty," from Old French oficial "official; main, principal" (14c., Modern French officiel) or directly from Late Latin officialis "of or belonging to duty, service, or office," from Latin officium (see office). Meaning "pertaining to an office or official position" is from c. 1600.
officialese (n.): "language of officialdom," 1881, from official + -ese.
officiant (n.): 1844, from noun use of Medieval Latin officiantem (nominative officians), present participle of officiare "perform religious services," from Latin officium (see office).
officiate (v.): 1630s, "to perform a duty," especially "to perform the duty of a priest," from Medieval Latin officiatum, from present participle of officiare "perform religious services," from Latin officium (see office). Related: Officiated; officiating.
officinal (adj.): "kept in stock by a druggist," c. 1720, from French officinal, from Medieval Latin officinalis, literally "of or belonging in an officina," a storeroom (of a monastery) for medicines and necessaries, in classical Latin "workshop, manufactory, laboratory," contraction of *opificina, from opifex (genitive opificis) "worker, workman, maker, doer" (from opus "work;" see opus) + -fex, -ficis "one who does," from facere "to make, do, perform" (see factitious). Related: Officinally.
officious (adj.): 1560s, "zealous, eager to serve," from Latin officiosus "full of courtesy, dutiful, obliging," from officium "duty, service" (see office). Sense of "meddlesome, doing more than is asked or required" had emerged by 1600 (in officiously). An officious lie (1570s) is one told to do good to another person (from Latin mendocium officiosum or French mensonge officieux). Related: Officiousness.
offing (n.): in phrase in the offing, 1779, from nautical term offing "the more distant part of the sea as seen from the shore" (1620s), from off (q.v.) + noun suffix -ing (1). Originally the phrase meant "in the distant future;" modern sense of "impending" developed 1914.
offset (n.): 1550s, "act of setting off" (on a journey, etc.), from off + set (adj.). Meaning "something 'set off' against something else, a counterbalance" is from 1769; the verb in this sense is from 1792. As a type of printing, in which the inked impression is first made on a rubber roller then transferred to paper, it is recorded from 1906.
offshoot (n.): 1670s, in figurative sense, of family trees; 1801 in general sense of "a derivative;" 1814 in literal sense, in reference to plants. From off + shoot (n.).
offshoring (n.): in the economic sense, as a form of outsourcing, attested by 1988, from offshore.
offside: also off-side, 1867, in various sporting senses, originally in English football; from off + side (n.).
offspring (n.): Old English ofspring "children or young collectively, descendants," literally "those who spring off (someone,)" from off + springan "to spring" (see spring (v.)). The figurative sense is first recorded c. 1600.
oft (adv.): Old English oft "often, frequently," from Proto-Germanic *ufta- "frequently" (source also of Old Frisian ofta, Danish ofte, Old High German ofto, German oft, Old Norse opt, Gothic ufta "often"), of unknown origin. Archaic except in compounds (such as oft-told), and replaced by its derivative often.
often (adv.): c. 1300, extended form of oft, originally before vowels and h-, probably by influence of Middle English selden "seldom." In common use from 16c., replacing oft.
oftentimes: extended form of often, attested from early 15c.
ogee (n.): "S-shaped molding," 1670s, from French ogive "diagonal rib of a vault," earlier augive, of unknown origin. Related: ogival.
ogham (n.): also ogam, ancient Irish form of writing, 1620s, from Irish ogham, from Old Irish ogam, said to be from name of its inventor, Ogma Mac Eladan. But this appears to be from Celt. *Ogmios, perhaps from PIE *og-mo- "furrow, track," thus metaphorically "incised line." This could be the source of the name of the writing style, which looks like a series of cuts or incised lines, and the inventor's name thus might be folk etymology. Related: Oghamic.
ogle (v.): 1680s, probably from Low German oeglen, frequentative of oegen "look at," from oege "eye," from Proto-Germanic *augon-, from PIE *okw- "to see" (see eye (n.)). Related to Dutch ogen "to look at," from oog "eye." Related: Ogled; ogling. The noun meaning "an amorous glance" is attested from 1711; earlier it meant "an eye" (1700).
ogre (n.): "man-eating giant," 1713, hogre (in a translation of a French version of the Arabian Nights), from French ogre, first used in Perrault's "Contes," 1697, and perhaps formed by him from Italian orco "demon, monster," from Latin Orcus "Hades," perhaps via an Italian dialect. In English, more literary than colloquial. The conjecture that it is from Byzantine Ogur "Hungarian" or some other version of that people's name (perhaps via confusion with the bloodthirsty Huns), lacks historical evidence. Related: Ogrish; ogrishness.
Ogygian (adj.): 1843, "of great antiquity or age," from Greek Ogygos, name of a mythical Attic or Boeotian king who even in classical times was thought to have lived very long ago. Also sometimes with reference to a famous flood said to have occurred in his day.
oh: 1530s, interjection expressing various emotions, a common Indo-European word (Old French ô;, oh; Latin o, oh; Greek o; Old Church Slavonic and Lithuanian o; Gothic, Dutch, German o; Old Irish a; Sanskrit a), but not found in Old English, which translated Latin oh with la or eala.
The present tendency is to restrict oh to places where it has a certain independence, & prefer o where it is proclitic or leans forward upon what follows .... [Fowler]
Often extended for emphasis, as in Oh, baby, stock saying from c. 1918; oh, boy (1910); oh, yeah (1924). Reduplicated form oh-oh as an expression of alarm or dismay is attested from 1944. Oh-so "so very" (often sarcastic or ironic) is from 1922. Oh yeah? "really? Is that so?" attested from 1930.
Ohio: originally used of the river, from Seneca (Iroquoian) ohi:yo', proper name from ohi:yo:h, literally "good river." The Seneca also used this of the Allegheny, which they considered the headwaters of the Ohio. Related: Ohian (1819); Ohioan (1818).
ohm (n.): unit of electrical resistance, 1867, in recognition of German physicist Georg S. Ohm (1789-1854), who determined the law of the flow of electricity. Originally proposed as ohma (1861) as a unit of voltage. Related: ohmage; ohmic; ohmeter.
oho (interj.): 14c., from oh + ho.
oi: 1962, vulgar or working class pronunciation of hoy a call or shout to attract attention.
oil (n.): late 12c., "olive oil," from Anglo-French and Old North French olie, from Old French oile, uile "oil" (12c., Modern French huile), from Latin oleum "oil, olive oil" (source of Spanish, Italian olio), from Greek elaion "olive tree," from elaia (see olive). Old English æle, Dutch olie, German Öl, etc. all are from Latin. It meant "olive oil" exclusively till c. 1300, when meaning began to be extended to any fatty, greasy substance. Use for "petroleum" first recorded 1520s, but not common until 19c. The artist's oils (1660s), short for oil-color (1530s), are paints made by grinding pigment in oil.
oil (v.): mid-15c., from oil (n.). Related: Oiled; oiling. An Old English verb in this sense was besmyrian.
oilcloth (n.): 1690s, "cotton or a similar fabric waterproofed with oil," from oil (n.) + cloth. In reference to an oil-treated canvas used as a cheap floor covering, 1796.
oily (adj.): 1520s, from oil (n.) + -y (2). Figurative meaning "smooth, unctuous" is from 1590s. Related: Oiliness.
oink (v.): "to make a noise like a pig," 1965, of imitative origin.
ointment (n.): late 13c., from Old French oignement "ointment, salve, unguent," from Vulgar Latin *unguimentum, from Latin unguentum (see unguent). The first -t- emerged in Old French from oint, past participle of verb oindre "to anoint."
OJ: slang abbreviation of orange juice, attested by 1963.