fillip (v.)

1590s "to fillip, to toss with the thumb," imitative, or perhaps a thinned form of flap, or else a contraction of fillip (q.v.), which also is held to be imitative. Meaning "toss as though with the thumb" is from 1610s. Meaning "to flip a coin" (to decide something) is by 1879. Sense of "get excited" is first recorded 1950; flip (one's) lid "lose one's head, go wild" is from 1949, American English; variant flip (one's) wig attested by 1952, but the image turns up earlier in popular record reviews ["Talking Boogie. Not quite as wig-flipping as reverse side--but a wig-flipper" Billboard, Sept. 17, 1949]. Related: Flipped. Flipping (adj.) as euphemism for fucking is British slang first recorded 1911 in D.H. Lawrence. Flip side (of a gramophone record) is by 1949.