The Collaborative International Dictionary of English v.0.48:

Jackanapes \Jack"a*napes\, n. [For Jack o' (= of) apes; prop., a
   man who exhibits apes.] [Written also jackanape.]
   [1913 Webster]
   1. A monkey; an ape. --Shak.
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   2. A coxcomb; an impertinent or conceited fellow.
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            A young upstart jackanapes.           --Arbuthnot.
      [1913 Webster] Jackaroo