Smack
mid 16th century (in the sense ‘part (one's lips) noisily’): from Middle Dutch smacken, of imitative origin; compare with German schmatzen ‘eat or kiss noisily’.
wiktionary
From Middle English smac, smak, smacke, from Old English smæc, smæċċ(“taste, smatch”), from Proto-Germanic *smakkuz(“a taste”), from Proto-Indo-European *smegʰ-, *smeg-(“to taste”). Cognate with English dialectal smatch, Scots smak(“scent, smell, taste, flavour”), Saterland Frisian Smoak(“taste”), West Frisian smaak(“taste”), Dutch smaak(“taste”), German Schmack, Geschmack(“taste”), Swedish and Norwegian smak(“taste”), Norwegian smekke . Akin to Old English smæċċan(“to taste, smack”). More at smake, smatch.
From Middle Low German smack (Low German Schmacke, Schmaake(“small ship”)) or Dutch smak, perhaps ultimately related to smakken, imitative of the sails' noise.
From Middle Dutch smacken, of imitative origin.
Akin to German schmatzen(“eat noisily”), Dutch smakken(“to fling down”), Plautdietsch schmaksen(“to smack the lips”), regional German schmacken, Schmackes(“vigour”) (compare Swedish smak(“slap”), Middle Low German smacken, the first part of Saterland Frisian smakmuulje(“smack”)).
etymonline
smack (n.1)
"a taste, flavor, savor" especially a slight flavor that suggests something, from Old English smæc "taste; scent, odor," from Proto-Germanic *smakka- (source also of Old Frisian smek, Middle Dutch smæck, Dutch smaak, Old High German smac, German Geschmack, Swedish smak, Danish smag), from verb *smakjanan, from a Germanic and Baltic root meaning "to taste" (source also of Lithuanian smaguriai "dainties," smagus "pleasing"). Meaning "a trace (of something)" is attested from 1530s.
smack (v.1)
"make a sharp noise with the lips," 1550s, probably of imitative origin (see smack (v.2)). With adverbial force, "suddenly, directly," from 1782; extended form smack-dab is attested from 1892, American English colloquial (slap-dab is from 1886).
smack (v.2)
"to slap a flat surface with the hand," 1835, from smack (n.) in this sense; perhaps influenced by Low German smacken "to strike, throw," which is likely of imitative origin (compare Swedish smak "slap," Middle Low German smacken, Frisian smakke, Dutch smakken "to fling down," Lithuanian smogti "to strike, knock down, whip").
smack (v.3)
mid-13c., "to smell (something"); mid-14c., "to taste (something), perceive by taste" (transitive); late 14c. "to have a taste, taste of" (intransitive), from smack (n.1). Compare Old English smæccan "to taste," Old Frisian smakia Middle Dutch smaecken, Old High German smakken "have a savor, scent, or taste," German schmecken "taste, try, smell, perceive." Sometimes also smatch. Now mainly in verbal figurative use smacks of ... (first attested 1590s). "Commonly but erroneously regarded as identical with [ smack (n.2)], as if 'taste' proceeds from 'smacking the lips.'" [Century Dictionary]
smack (n.2)
"smart, sharp sound made by the lips," 1560s, from smack (v.1). Meaning "a loud kiss" is recorded from c. 1600. Meaning "sharp sound made by hitting something with the flat of the hand" is from c. 1746.
smack (n.3)
single-masted sailboat, 1610s, probably from Dutch or Low German smak "sailboat," perhaps from smakken "to fling, dash" (see smack (v.2)), perhaps so-called from the sound made by its sails. French semaque, Spanish zumaca, Italian semacca probably are Germanic borrowings.
smack (n.4)
"heroin," 1942, American English slang, probably an alteration of schmeck "a drug," especially heroin (1932), from Yiddish schmeck "a sniff," from Germanic (see smack (n.1)).
