1610s, "a swindler;" 1650s, "anything intended to lead (someone) into a snare;" 1660s, "a lure employed in enticing game into a snare or within range of a weapon;" perhaps from Dutch kooi "cage," used of a pond surrounded by nets, into which wildfowl were lured for capture, from West Germanic *kaiwa, from Latin cavea "cage" (from cavus "a hollow" (from PIE root *keue- "to swell," also "vault, hole").
The first element is possibly the Dutch definite article de, mistaken in English as part of the word. If this is right, the later sense in English is the etymological one. But decoy, of unknown origin, was the name of a card game popular c. 1550-1650, and this may have influenced the form of the word.
1590s, "to entice, seduce, lead astray" (from allegiance, family, etc.), from French débaucher "entice from work or duty," from Old French desbaucher "to lead astray," a word of uncertain origin.
Supposedly it is literally "to trim (wood) to make a beam" (from bauch "beam," from Frankish balk or some other Germanic source akin to English balk (n.)). The notion of "shaving" something away, perhaps, but the root is also said to be a word meaning "workshop," which gets toward the notion of "to lure someone off the job;" either way the sense evolution is unclear.
The more specific meaning "seduce from virtue or morality, corrupt the morals or principles of" is from c. 1600, especially "to corrupt with lewdness, seduce sexually," usually in reference to women. Intransitive sense "indulge in excess in sensual enjoyment" is from 1640s. As a noun, "a bout of excessive sensual pleasure," c. 1600.
acronym for sealed with a kiss, attested from 1911, in a legal publication quoting a letter from 1909:
"... Well Kid I don't know nothing else to say only that I hope to see your sweet face Sat. Good by from your Dear Husban to his sweet little wife. P. S. excuse bad writing and mispelled words take all mistakes as kisses. S.W.A.K. * * *" This letter was postmarked at Des Moines October 20, 1909, addressed to Carrie Sprague at Jefferson, Iowa, and reached the latter place October 21, 1909. [State v. Manning (a conspiracy-to-lure-women-to-prostitution case), Supreme Court of Iowa, Nov. 16, 1910, reported in Northwestern Reporter, vol. cxxviii, 1911]
Popularized in soldiers' letters home in World War I. It probably is meant also to echo the sound of a kiss. Compare Middle English swack "a hard blow" (late 14c.).
late 14c., "to go about, stroll," later (early 15c.) "roll from side to side, trundle," probably from Old French troller, a hunting term, "wander, to go in quest of game without purpose" (Modern French trôler), from a Germanic source (compare Old High German trollen "to walk with short steps"), from Proto-Germanic *truzlanan.
Sense of "sing in a full, rolling voice" (first attested 1570s) and that of "fish with a moving line" (c. 1600) both are extended technical uses from the general sense of "roll, trundle," the former from "sing in the manner of a catch or round," the latter perhaps confused with trail or trawl. Figurative sense of "to lure on as with a moving bait, entice, allure" is from 1560s. Meaning "to cruise in search of sexual encounters" is recorded from 1967, originally in homosexual slang.
The internet sense (everyone seems to have his own definition of it) seems to date to the late 1980s or early 1990s and the Newsgroups era, and the verbal use is perhaps older than the noun. It seems to combine troll (v.) in the "fish with a moving line" sense (itself confused with trawl) and troll (n.1) "troublesome imp supposed to live underground."
"fabled marine or amphibian creature having the upper body in the form of a woman and the lower in the form of a fish, with human attributes," "usually working harm, with or without malignant intent, to mortals with whom she might be thrown into relation" [Century Dictionary]; mid-14c., meremayde, literally "maid of the sea," from Middle English mere "sea, lake" (see mere (n.1)) + maid.
Old English had equivalent merewif "water-witch" (see wife), meremenn "mermaid, siren" (compare Middle Dutch meer-minne, Old High German meri-min), which became Middle English mere-min (c. 1200) and was shortened to mere "siren, mermaid" (early 13c.); the later mermaid might be a re-expansion of this. Tail-less in northern Europe; the fishy form is a medieval influence from the classical siren, and mermaids sometimes were said to lure sailors to destruction with song.
A favorite sign of taverns and inns at least since early 15c. (in reference to the inn on Bread Street, Cheapside, London). Mermaid pie (1660s) was "a sucking pig baked whole in a crust." Mermaid's purse for "egg-case of a skate, ray, or shark" is by 1825, perhaps originally Scottish, as it is first attested in Jamieson.