jackanapes

noun

1. an impertinent, presumptuous person, especially a young man; whippersnapper.
2. an impudent, mischievous child.
3. Archaic. an ape or monkey.

noun

1. a conceited impertinent person
2. a mischievous child
3. archaic a monkey

n.

mid-15c., “a monkey,” also “an impertinent, conceited fellow;” apparently from Jack of Naples, but whether this is some specific personification or folk etymology of jack (n.) + ape is unknown. See note in OED.