Английский Этимологический словарь - flirt (v.)

- 1553, originally "to rap or flick, as with the fingers," later "to turn up one's nose, sneer at." Possibly related to E.Fris. flirt "a flick or light blow," and flirtje "a giddy girl." The sense "play at courtship" is 1777, likely influenced by O.Fr. fleureter "to touch a thing in passing," metaphoric of bees skimming from flower to flower. The noun meaning "person who flirts" is from 1732.