[1] : The Collaborative International Dictionary of English v.0.48

perk \perk\ p~erk, v. t. imp.  p. p. perked p~erkt;
   p. pr.  vb. n. perking. cf. w. percu to trim, to make
   smart.
   to make trim or smart; to straighten up; to erect; to make a
   jaunty or saucy display of; as, to perk the ears; to perk up
   one's head. --cowper. --sherburne.
   1913 webster

   to perk up one's ears to begin to listen attentively; --
      usually used when something of interest is mentioned in
      some discourse, after one's attention had lapsed; as, he
      perked up his ears when he heard his name mentioned.
      pjc
see also:
perked perking to perk up one's ears 

[2] : WordNet (r) 2.0

perked
     adj : especially of ears quickly lifted up or out in attention;
           `perched' is obsolete; "a dog with perked ears" syn: perched,
            perked up
see also:
perched perked up 

Perked >> P Words
Perked, definition of term: Perked
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