crevice (n.)youdaoicibaDictYouDict[crevice 词源字典]
mid-14c., from Old French crevace (12c., Modern French crevasse) "gap, rift, crack" (also, vulgarly, "the female pudenda"), from Vulgar Latin *crepacia, from Latin crepare "to crack, creak" (see raven); meaning shifted from the sound of breaking to the resulting fissure.[crevice etymology, crevice origin, 英语词源]
cunt (n.)youdaoicibaDictYouDict
"female intercrural foramen," or, as some 18c. writers refer to it, "the monosyllable," Middle English cunte "female genitalia," by early 14c. (in Hendyng's "Proverbs" -- ʒeve þi cunte to cunni[n]g, And crave affetir wedding), akin to Old Norse kunta, Old Frisian, Middle Dutch, and Middle Low German kunte, from Proto-Germanic *kunton, which is of uncertain origin. Some suggest a link with Latin cuneus "wedge," others to PIE root *geu- "hollow place," still others to PIE *gwen-, root of queen and Greek gyne "woman."

The form is similar to Latin cunnus "female pudenda" (also, vulgarly, "a woman"), which is likewise of disputed origin, perhaps literally "gash, slit," from PIE *sker- (1) "to cut," or literally "sheath," from PIE *kut-no-, from root *(s)keu- "to conceal, hide."
Hec vulva: a cunt. Hic cunnus: idem est. [from Londesborough Illustrated Nominale, c. 1500, in "Anglo-Saxon and Old English Vocabularies," eds. Wright and Wülcker, vol. 1, 1884]
First known reference in English apparently is in a compound, Oxford street name Gropecuntlane cited from c. 1230 (and attested through late 14c.) in "Place-Names of Oxfordshire" (Gelling & Stenton, 1953), presumably a haunt of prostitutes. Used in medical writing c. 1400, but avoided in public speech since 15c.; considered obscene since 17c.

in Middle English also conte, counte, and sometimes queinte, queynte (for this, see q). Chaucer used quaint and queynte in "Canterbury Tales" (late 14c.), and Andrew Marvell might be punning on quaint in "To His Coy Mistress" (1650).
"What eyleth yow to grucche thus and grone? Is it for ye wolde haue my queynte allone?" [Wife of Bath's Tale]
Under "MONOSYLLABLE" Farmer lists 552 synonyms from English slang and literature before launching into another 5 pages of them in French, German, Italian, Spanish, and Portuguese. [A sampling: Botany Bay, chum, coffee-shop, cookie, End of the Sentimental Journey, fancy bit, Fumbler's Hall, funniment, goatmilker, heaven, hell, Itching Jenny, jelly-bag, Low Countries, nature's tufted treasure, parenthesis, penwiper, prick-skinner, seminary, tickle-toby, undeniable, wonderful lamp, and aphrodisaical tennis court, and, in a separate listing, Naggie. Dutch cognate de kont means "a bottom, an arse," but Dutch also has attractive poetic slang ways of expressing this part, such as liefdesgrot, literally "cave of love," and vleesroos "rose of flesh."

Alternative form cunny is attested from c. 1720 but is certainly much earlier and forced a change in the pronunciation of coney (q.v.), but it was good for a pun while coney was still the common word for "rabbit": "A pox upon your Christian cockatrices! They cry, like poulterers' wives, 'No money, no coney.' " [Philip Massinger: "The Virgin-Martyr," Act I, Scene 1, 1622]
merkin (n.)youdaoicibaDictYouDict
"female pudenda," 1530s, apparently a variant of malkin in its sense of "mop." Meaning "artificial vagina or 'counterfeit hair for a woman's privy parts' " is attested from 1610s. According to "The Oxford Companion to the Body," the custom of wearing merkins dates from mid-15c., was associated with prostitutes, and was to disguise a want of pubic hair, shaved off either to exterminate body lice or evidence of venereal disease.
This put a strange Whim in his Head; which was, to get the hairy circle of [a prostitute's] Merkin .... This he dry'd well, and comb'd out, and then return'd to the Cardinall, telling him, he had brought St. Peter's Beard. [Alexander Smith, "A Complete History of the Lives and Robberies of the most notorious Highwaymen," 1714]
naff (v.)youdaoicibaDictYouDict
British slang word with varied uses, not all certainly connected; see Partridge, who lists three noun uses: 1. "female pudenda" (c. 1845), which might be back-slang from fan, shortening of fanny (in the British sense); 2. "nothing," in prostitutes' slang from c. 1940; 3. a euphemism for fuck (v.) in oaths, imprecations, expletives (as in naff off), 1959, "making it slightly less obvious than eff" [Partridge]; and an adjective naff "vulgar, common, despicable," said to have been used in 1960s British gay slang for "unlovely" and thence adopted into the slangs of the theater and the armed forces.
private (adj.)youdaoicibaDictYouDict
late 14c., "pertaining or belonging to oneself, not shared, individual; not open to the public;" of a religious rule, "not shared by Christians generally, distinctive; from Latin privatus "set apart, belonging to oneself (not to the state), peculiar, personal," used in contrast to publicus, communis; past participle of privare "to separate, deprive," from privus "one's own, individual," from PIE *prei-wo-, from PIE *prai-, *prei-, from root *per- (1) "forward, through" (see per).

Old English in this sense had syndrig. Private grew popular 17c. as an alternative to common (adj.), which had overtones of condescension. Of persons, "not holding public office," recorded from early 15c. In private "privily" is from 1580s. Related: Privately. Private school is from 1650s. Private parts "the pudenda" is from 1785. Private enterprise first recorded 1797; private property by 1680s; private sector is from 1948. Private eye "private detective" is recorded from 1938, American English.
pudendum (n.)youdaoicibaDictYouDict
"external genitals," late 14c. (pudenda), from Latin pudendum (plural pudenda), literally "thing to be ashamed of," neuter gerundive of pudere "make ashamed; be ashamed," from PIE root *(s)peud- "to punish, repulse." Translated into Old English as scamlim ("shame-limb"); in Middle English also anglicized as pudende (early 15c.). Related: Pudendal.
pussy (n.2)youdaoicibaDictYouDict
slang for "female pudenda," 1879, but probably older; perhaps from Old Norse puss "pocket, pouch" (compare Low German puse "vulva"), but perhaps instead from the cat word (see pussy (n.1)) on notion of "soft, warm, furry thing;" compare French le chat, which also has a double meaning, feline and genital. Earlier uses are difficult to distinguish from pussy (n.1), as in:
The word pussie is now used of a woman [Philip Stubbes, "The Anatomie of Abuses," 1583]
But the absence of pussy in Grose and other early slang works argues against the vaginal sense being generally known before late 19c., as does its frequent use as a term of endearment in mainstream literature, as in:
"What do you think, pussy?" said her father to Eva. [Harriet Beecher Stowe, "Uncle Tom's Cabin," 1852]
Pussy-whipped first attested 1956.
tail (n.1)youdaoicibaDictYouDict
"hindmost part of an animal," Old English tægl, tægel "a tail," from Proto-Germanic *tagla- (cognates: Old High German zagal, German Zagel "tail," dialectal German Zagel "penis," Old Norse tagl "horse's tail," Gothic tagl "hair"), from PIE *doklos, from suffixed form of root *dek- (2) "something long and thin" (referring to such things as fringe, lock of hair, horsetail; cognates: Old Irish dual "lock of hair," Sanskrit dasah "fringe, wick"). According to OED, the primary sense, at least in Germanic, seems to have been "hairy tail," or just "tuft of hair," but already in Old English the word was applied to the hairless "tails" of worms, bees, etc. But Buck writes that the common notion is of "long, slender shape." As an adjective from 1670s.

Meaning "reverse side of a coin" (opposite the side with the head) is from 1680s; that of "backside of a person, buttocks" is recorded from c. 1300; slang sense of "pudenda" is from mid-14c.; that of "woman as sex object" is from 1933, earlier "act of copulation" with a prostitute (1846). Of descending strokes of letters, from 1590s.

Tails "coat with tails" is from 1857. The tail-race (1776) is the part of a mill race below the wheel. To turn tail "take flight" (1580s) originally was a term in falconry. The image of the tail wagging the dog is attested from 1907. Another Old English word for "tail" was steort (see stark).
wife (n.)youdaoicibaDictYouDict
Old English wif (neuter) "woman, female, lady," also, but not especially, "wife," from Proto-Germanic *wiban (cognates: Old Saxon, Old Frisian wif, Old Norse vif, Danish and Swedish viv, Middle Dutch, Dutch wijf, Old High German wib, German Weib), of uncertain origin, not found in Gothic.

Apparently felt as inadequate in its basic sense, leading to the more distinctive formation wifman (source of woman). Dutch wijf now means, in slang, "girl, babe," having softened somewhat from earlier sense of "bitch." German cognate Weib also tends to be slighting or derogatory and has been displaced by Frau.

The more usual Indo-European word is represented in English by queen/quean. Words for "woman" also double for "wife" in some languages. Some proposed PIE roots for wife include *weip- "to twist, turn, wrap," perhaps with sense of "veiled person" (see vibrate); and more recently *ghwibh-, a proposed root meaning "shame," also "pudenda," but the only examples of it would be the Germanic words and Tocharian (a lost IE language of central Asia) kwipe, kip "female pudenda."

The modern sense of "female spouse" began as a specialized sense in Old English; the general sense of "woman" is preserved in midwife, old wives' tale, etc. Middle English sense of "mistress of a household" survives in housewife; and the later restricted sense of "tradeswoman of humble rank" in fishwife. By 1883 as "passive partner in a homosexual couple." Wife-swapping is attested from 1954.