The Collaborative International Dictionary of English v.0.48:

Caper \Ca"per\, v. i. [imp. & p. p. Capered p. pr. & vb. n.
   capering.] [From older capreoll to caper, cf. F. se cabrer
   to prance; all ultimately fr. L. caper, capra, goat. See
   Capriole.]
   To leap or jump about in a sprightly manner; to cut capers;
   to skip; to spring; to prance; to dance.
   [1913 Webster]

         He capers, he dances, he has eyes of youth. --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Caper \Ca"per\, n.
   A frolicsome leap or spring; a skip; a jump, as in mirth or
   dancing; a prank.
   [1913 Webster]

   To cut a caper, to frolic; to make a sportive spring; to
      play a prank. --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Caper \Ca"per\, n. [D. kaper.]
   A vessel formerly used by the Dutch, privateer. --Wright.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Caper \Ca"per\, n. [F. c[^a]pre, fr. L. capparis, Gr. ?; cf. Ar.
   & Per. al-kabar.]
   1. The pungent grayish green flower bud of the European and
      Oriental caper (Capparis spinosa), much used for
      pickles.
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   2. (Bot.) A plant of the genus Capparis; -- called also
      caper bush, caper tree.
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   Note: The Capparis spinosa is a low prickly shrub of the
         Mediterranean coasts, with trailing branches and
         brilliant flowers; -- cultivated in the south of Europe
         for its buds. The Capparis sodada is an almost
         leafless spiny shrub of central Africa (Soudan),
         Arabia, and southern India, with edible berries.
         [1913 Webster]

   Bean caper. See Bran caper, in the Vocabulary.

   Caper sauce, a kind of sauce or catchup made of capers.
      [1913 Webster]

WordNet (r) 3.0 (2006):

caper
    n 1: any of numerous plants of the genus Capparis
    2: pickled flower buds used as a pungent relish in various
       dishes and sauces
    3: a crime (especially a robbery); "the gang pulled off a bank
       job in St. Louis" [syn: caper, job]
    4: a playful leap or hop [syn: caper, capriole]
    5: gay or light-hearted recreational activity for diversion or
       amusement; "it was all done in play"; "their frolic in the
       surf threatened to become ugly" [syn: play, frolic,
       romp, gambol, caper]
    6: a ludicrous or grotesque act done for fun and amusement [syn:
       antic, joke, prank, trick, caper, put-on]
    v 1: jump about playfully

Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "caper":
   antic, beam, bob, bounce, burglary, capriole, caracole, carol,
   carry on, cavort, chirp, chirrup, clap hands, crime, curvet,
   cut a dido, cut capers, cut up, dance, delight, devilment, dido,
   disport, escapade, exult, falcade, filch, flounce, fool around,
   frisk, frolic, gambade, gambado, gambol, glory, glow, grab, heist,
   high jinks, hop, horse around, impishness, job, joy, jubilate,
   jump, jump about, lark, laugh, leap, lift, lilt, mischief,
   monkeyshine, monkeyshines, pinch, play, practical joke, prance,
   prank, radiate cheer, ramp, rejoice, revel, rip-off, robbery,
   roguery, rollick, romp, shenanigan, shenanigans, shines, sing,
   skip, skip for joy, smile, sparkle, sport, spring, steal, stunt,
   theft, tomfoolery, trick, trip, waggish trick, waggishness,
   whistle