This word for the female genitalia dates back to the Middle English period, c.1325. It’s exact origin is unknown, but is related to the Old Norse kunta, a word with cognates in several other Germanic languages. From the Proverbs of Hendyng, a manuscript from sometime before 1325:
Ȝeue þi cunte to cunnig and craue affetir wedding.
(Give your cunt wisely and ask for what is due after the wedding.)
There is a potentially earlier usage in the name of a London street, Gropecuntelane, from c.1230.
Also likely to be related is the noun quaint, which in Middle English was used to denote the female genitalia. From Sir Tristrem from c.1320:
Hir queynt abouen hir kne, Naked þe kniȝtes knewe.
(Her quaint above her knee, Naked the knight knew.)
And as most English Literature students have discovered, it is used in Chaucer’s The Miller’s Tale (c.1386):
Pryvely he caught hir by the queynte.
(Secretly he grabbed her by the quaint.)
Use of cunt as term of abuse for a woman is a 20th century sense. From Frederic Manning’s 1929 The Middle Parts of Fortune:
What’s the cunt want to come down ‘ere buggering us about for, ‘aven’t we done enough bloody work in th’ week?
Cunt does not come from the Latin cunnus, which is also a term for the female pudenda, although a common root back in the mists of time cannot be discounted.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2016, by David Wilton