English
freebox
From free (“unconstrained”) + box (“vagina”).
A compound of free ‘unconstrained’ + box ‘vagina’
Proto-Indo-European *preyH- ‘to please; to love’
…
Proto-Germanic *frijaz ‘free’
Proto-West Germanic *frī ‘free’
Old English frēo ‘free, at liberty’
Middle English fre ‘having the status of a freeman’
English free
Late Latin buxis ‘box’
Proto-West Germanic *buhsā ‘box’
Old English box ‘box, case’
Middle English box ‘container’
English box
The story
Modelled on freeball (‘(of a man) to forgo wearing underwear under one's outer bottomwear’).
Today it means
verb (of a woman) To forgo underpants beneath one's dress, skirt, trousers, etc.
Language periods are conventional ranges, not dates for this word.
Etymograph / freebox