1. an impertinent, presumptuous person, especially a young man; whippersnapper.
2. an impudent, mischievous child.
3. Archaic . an ape or monkey.
1400–50; late Middle English Jakken-apes, literally, jack (i.e., man) of the ape, nickname of William de la Pole (1396–1450), Duke of Suffolk, whose badge was an ape’s clog and chain