(Noun) One who is like an ape in tricks, airs, or behavior; a ridiculous upstart; a pert, impertinent fellow, who assumes ridiculous airs; a coxcomb. Also, playfully, a pert forward child, a “monkey.”
“‘God, what’s the Navy coming to, when warrants are given to young jackanapes who couldn’t keep their noses clear with a marlin-spike!'”
C. S. Forester, Commodore Hornblower, 1945.