English
French leave
From French (adjective) + leave (noun), apparently from a French custom, already recorded in the 18th century, of leaving from receptions or other events without formally announcing one’s departure to the host or hostess.
Proto-Germanic *frankô ‘spear’
Proto-West Germanic *Frankō ‘a Frank’
Old English Franca ‘a Frank’
Old English Frencisc ‘of the Franks, Frankish, French’
Middle English French
English French
Proto-Indo-European *leyp- ‘to stick’
…
Proto-Germanic *laibijaną ‘to let stay’
Proto-West Germanic *laibijan ‘to leave behind’
Old English lǣfan ‘to leave’
Middle English leven ‘to leave’
English leave
Today it means
noun A departure taken quietly and unnoticed, without asking for permission or informing anyone.
Language periods are conventional ranges, not dates for this word.
Etymograph / French leave