Online Etymology Dictionary

SMERSH (n.): Soviet Army counter-espionage organization begun during World War II, 1953, from Russian abbreviation of smert' shpionam "death to spies." Introduced in English by Ian Flemming.
smidge (n.): short form of smidgen, 1905, American English dialect.
smidgen (n.): 1845, perhaps from Scot. smitch "very small amount, small insignificant person" (1822), perhaps from smidin "small syllable."
smilax: c.1600, from Latin, from Greek smilax "blindweed."
smile (v.): c.1300, perhaps from Middle Low German *smilen or a Scandinavian source (e.g. Danish smile, Swedish smila "smile"), from PIE root *smei- (cf. Old English smerian "to laugh at," Old High German smieron "to smile," Latin mirus "wonderful").

Gradually pushed the usual Old English word, smearcian (modern smirk), into a specific, unpleasant sense. Related: Smiled; smiling. Romance, Celtic, and Slavic languages tend to use a diminutive of the word for "laugh" to mean "smile" (e.g. Latin ridere "laugh;" subridere "smile"), with perhaps a literal notion of "small laugh," or "low laugh."
smile (n.): 1560s, from smile (v.).
smirch (v.): late 15c., "to discolor, to make dirty," perhaps from Old French esmorcher "to torture," perhaps also "befoul, stain," from es- "out" + morcher "to bite," from Latin morsus, past participle of mordere "to bite" (see smart (v.)). Sense of "dishonor, disgrace, discredit" first attested 1820.
smirk (v.): Old English smearcian "to smile." No exact cognates in other languages, but perhaps related to smerian "to laugh at" (see smile (v.)). Related: Smirked; smirking. The noun is recorded by 1560s.
Smirnoff: proprietary name of a brand of vodka, said to have been in use since 1914.
smite (v.): Old English smitan "to hit, strike, beat" (strong verb, past tense smat, past participle smiten), from Proto-Germanic *smitanan (cf. Swedish smita, Danish smide "to smear, fling," Old Frisian smita, Middle Low German, Middle Dutch smiten "to cast, fling," Dutch smijten "to throw," Old High German smizan "to rub, strike," German schmeißen "to cast, fling," Gothic bismeitan "to spread, smear"), perhaps from PIE root *(s)mei- "to smear, to rub," but original sense in Germanic seems to be of throwing. Sense of "slay in combat" (c.1300) is originally Biblical, smite to death, first attested c.1200.
smith (n.): Old English smið "one who works in metal" (jewelers as well as blacksmiths), from Proto-Germanic *smithaz "skilled worker" (cf. Old Saxon smith, Old Norse smiðr, Danish smed, Old Frisian smith, Old High German smid, German Schmied, Gothic -smiþa, in aiza-smiþa "coppersmith"), from PIE root *smei- "to carve, cut" (cf. Greek smile "knife, chisel"). Attested as a surname since at least c.975.
Smith & Wesson: proprietary name of a type of firearm, 1860, from the gunsmith firm of Horace Smith (1808-1893) and Daniel B. Wesson (1825-1906) in Springfield, Massachusetts.
smithereens (n.): "fragments," 1829, from Irish smidirin, diminutive of smiodar "fragment," perhaps with diminutive ending as in Colleen.
Smithfield: place in London, celebrated since at least 17c. as a market for cattle and horses, later the central meat market. In various colloquial expressions. Originally Smethefield, from Old English smethe "smooth." Smithfield ham (1908, American English) is from a town of that name in Virginia.
Smithsonian: "Smithsonian Institute," named for founder James Smithson (1765-1829).
smithy (n.): Old English smiððe, from Proto-Germanic *smithjon; see smith.
smitten (adj.): mid-13c., past participle of smite. Sense of "inspired with love" is from 1660s.
smock (n.): Old English smoc "woman's garment," from Proto-Germanic *smukkaz (cf. Old Norse smokkr, but this is perhaps from Old English, Old High German smoccho "smock," a rare word, North Frisian smok, but this, too, perhaps from English), from PIE root *smeugh- "to press" (cf. Old Church Slavonic smykati se "to creep"). Original notion seems to be "garment one creeps into," as the word is related to Old Norse smjuga "to creep into (a garment)" and Old English smugan "to creep" and smygel "a burrow." Cf. also German schmiegen "to cling to, to press close, nestle," hence Middle High German verb smucken, German schmucken "to adorn."

English smock was common down to 18c., and was emblematic of womanhood generally, cf. verb smock "to render (a man) effeminate or womanish" (1610s); smock-face "person having a pale, effeminate face" (c.1600). Replaced by euphemistic shift (n.2). Modern meaning "woman's or child's loose dress or blouse" is from 1907; sense of "loose garment worn by artists over other clothes" is from 1938.
smog (n.): 1905, blend of smoke and fog, formed "after Lewis Carrol's example" [Klein; see portmanteau]. Reputedly coined in reference to London, and first attested there in a paper read by Dr. H.A. des Voeux, treasurer of the Coal Smoke Abatement Society, though he seems not to have claimed credit for coining it.
At a recent health congress in London, a member used a new term to indicate a frequent London condition, the black fog, which is not unknown in other large cities and which has been the cause of a great deal of bad language in the past. The word thus coined is a contraction of smoke fog "smog" -- and its introduction was received with applause as being eminently expressive and appropriate. It is not exactly a pretty word, but it fits very well the thing it represents, and it has only to become known to be popular. ["Journal of the American Medical Association," Aug. 26, 1905]
smoke (n.1): late Old English smoca, related to smeocan "give off smoke," from Proto-Germanic *smeukanan (cf. Middle Dutch smooc, Dutch smook, Middle High German smouch, German Schmauch), from PIE root *smeug(h)- "to smoke" (cf. Armenian mux "smoke," Greek smykhein "to burn with smoldering flame," Old Irish much, Welsh mwg "smoke"). Smoke-eater "firefighter" is c.1930. Phrase go up in smoke "be destroyed" is from 1933. Smoke alarm first attested 1936.
smoke (v.): Old English smocian "to produce smoke," see smoke (n.). Meaning "to drive out or away or into the open by means of smoke" is attested from 1590s. Meaning "to cure (bacon, fish, etc.) by exposure to smoke" is first attested 1590s. In connection with tobacco, the verb is first recorded 1604 in James I's "Counterblast to Tobacco." Related: Smoked; smoking. Smoking gun in figurative sense of "incontestable evidence" is from 1974.
smoke (n.2): "cigarette," slang, 1882, from smoke (n.1). Also "opium" (1884). Meaning "a spell of smoking tobacco" is recorded from 1835.
smoke screen (n.): 1915, as a form of military camouflage, from smoke (n.1); 1926 in the figurative sense. The association of smoke with "deception, deliberate obscurity" dates back to at least 1565.
smoker (n.): 1590s, "one who cures meat," agent noun from smoke (v.). Meaning "one who smokes tobacco" is from 1610s.
smokestack (n.): 1862, from smoke (n.) + stack (n.).
smokey: variant of smoky. Also sometimes short for Smokey Bear.
Smokey Bear (n.): "state policeman," 1974, from truckers' slang, in reference to the wide-brim style of hat worn by state troopers (the hats so called by 1969). Ultimately the reference is to an illustrated character of that name, dressed in forest ranger gear, introduced in 1944 by the U.S. Forest Service and the Wartime Advertising Council in a campaign to lower the number of forest fires in the West.
smoky (adj.): early 14c., from smoke (n.) + -y (2). Of flavors, from 1540s; of colors, from 1550s.
smolder (v.): c.1300 (implied in smoldering), "to smother, suffocate," cognate with Middle Dutch smolen, Low German smelen, Flemish smoel "hot," from Proto-Germanic *smel-, *smul-. The meaning "burn and smoke without flame" is first recorded 1520s, fell from use 17c. (though smoldering persisted in poetry) and was revived 19c. Related: Smouldered.
smooch: 1932 (v.); 1942 (n.), alteration of dialectal verb smouch (1570s), possibly imitative of the sound of kissing (cf. German dialectal schmutzen "to kiss"). Related: Smooched; smooching.
smooth (adj.): Old English smoð "free from roughness, not harsh," of unknown origin. Sense of "pleasant, polite, sincere" first recorded late 14c. Slang meaning "superior, classy, clever" is attested from 1893. Smooth-bore in reference to guns is from 1812. smooth talk (v.) is recorded from 1950. A 1599 dictionary has smoothboots "a flatterer, a faire spoken man, a cunning tongued fellow." The usual Old English form was smeðe, and there is a dialectal smeeth found in places names, e.g. Smithfield, Smedley.
smooth (v.): late Old English smeþan, smeþian "to become smooth," from the source of smooth (adj.). Meaning "to make smooth" is c.1200. Related: Smoothed; smoothing.
smoothie (n.): 1929, "suave person," from smooth + -ie. As a type of blender drink, by 1983.
smorgasbord (n.): 1893, from Swedish smörgåsbord "open sandwich table," literally "butter-goose table," from smörgås, which is said to mean "bread and butter," but is compounded from smör "butter" (related to smear) and gås, literally "goose" (and from the root of English goose (n.)), which is said to have a secondary meaning of "a clump (of butter)." The final element is bord "table" (cf. board (n.1)). Figurative sense of "medley, miscellany" is recorded from 1948.
smote: past tense of smite (q.v.).
smother (v.): c.1200, "to suffocate with smoke," from smorthre (n.) "dense, suffocating smoke" (late 12c.), from stem of Old English smorian "to suffocate, choke," possibly connected to smolder. Meaning "to kill by suffocation" is from 1540s; sense of "to extinguish a fire" is from 1590s. Sense of "stifle, repress" is first recorded 1570s; meaning "to cover thickly (with some substance)" is from 1590s. Related: Smothered; smothering.
smoulder (v.): see smolder.
smudge (v.): early 15c., smogen "to soil, stain, blacken," of obscure origin. Related: Smudged; smudging. The noun is first attested 1768, from the verb.
smug (adj.): 1550s, "trim, neat, spruce, smart," possibly an alteration of Low German smuk "trim, neat," from Middle Low German smücken "to adorn," and smiegen "to press close" (see smock). The meaning "having a self-satisfied air" is from 1701, an extension of the sense of "smooth, sleek" (1580s), which was commonly used of attractive women and girls. Related: Smugly; smugness.
smuggle (v.): 1680s, of Low German or Dutch origin (see smuggler). Related: Smuggled; smuggling.
smuggler (n.): 1660s, from Low German smuggeln or Dutch smokkelen "to transport (goods) illegally," apparently a frequentative formation of a word meaning "to sneak" (from Proto-Germanic *smuganan) and related to smock (q.v.).
smush: 1825 (n.), variant of mush. As a verb, by 1980.
smut (n.): 1660s, "black mark, stain," from verb smutten "debase, defile" (early 15c.), cognate with Middle High German smotzen "make dirty," from West Germanic *smutt- (cf. Middle High German smuz "grease, dirt;" German Schmutz "dirt," schmutzen "to make dirty"). The meaning "indecent or obscene language" is first attested 1660s.
smutch (v.): 1610s, variant of smudge (q.v.).
smutty (adj.): 1660s, in the "indecent" sense, from smut + -y (2).
snack (v.): c.1300, "to bite or snap" (of a dog), probably from Middle Dutch snacken "to snatch, chatter" (see snatch (v.)). The meaning "have a mere bite or morsel, eat a light meal" is first attested 1807. Related: Snacked; snacking.
snack (n.): "bite or morsel to eat," 1757, from snack (v.). Snack bar is attested from 1930.
snaffle (n.): "simple bridle-bit," 1530s, perhaps from Dutch snavel "beak, bill;" cf. German Schnabel "beak, face," Old English nebb, Old Norse neff "beak, nose," from PIE root *snab- "beak" (see neb).
snafu (n.): 1941, U.S. military slang, acronym for situation normal, all fucked up, "conveying the common soldier's laconic acceptance of the disorder of war and the ineptitude of his superiors" ["Oxford English Dictionary," which seldom fails to delight].
snag (n.): 1570s, "stump of a tree, branch," of Scandinavian origin, cf. Old Norse snagi "clothes peg," snaga "a kind of ax." The meaning "sharp or jagged projection" is first recorded 1580s; that of "obstacle, impediment" is 1829. Snaggle-toothed "having crooked, projecting teeth" (1580s) is from the same root.