of certain animals, "to engage in courtship displays," 1871, probably from Swedish leka "to play," cognate of English dialectal verb lake (see lark (n.2)). Related: Lekking.
Entries linking to lek
lark n.2
"spree, frolic, merry adventure," 1811, slang, of uncertain origin. Possibly a shortening of skylark (1809), sailors' slang for "play rough in the rigging of a ship" (larks were proverbial for high-flying). Or perhaps it is an alteration of English dialectal or colloquial lake/laik "to play, frolic, make sport" (c. 1300, from Old Norse leika "to play," from PIE *leig- (3) "to leap") with unetymological -r- common in southern British dialect. The verb lake, considered characteristic of Northern English vocabulary, is the opposite of work but lacks the other meanings of play. As a verb, from 1813. Related: Larked; larking.