The slang term minge in the sense of quim dates from the beginning of the 20th century. However, neither the OED nor Etymonline has any idea where it came from.
Here are two of the OED’s citations:
- 1936 J. Curtis Gilt Kid viii. 80 — I’m going to give you a kick in the minge if you don’t shut up. 1974 New Direction IV. iv. 19/2 — They’ve all..scented and talced their minges.
Which is all very nice and all, but what is the origin of the word in this sense?