The Collaborative International Dictionary of English v.0.48:

Carp \Carp\ (k[aum]rp), v. i. [imp. & p. p. Carped
   (k[aum]rpt); p. pr. & vb. n. Carping.] [OE. carpen to say,
   speak; from Scand. (cf. Icel. karpa to boast), but influenced
   later by L. carpere to pluck, calumniate.]
   1. To talk; to speak; to prattle. [Obs.] --Chaucer.
      [1913 Webster]

   2. To find fault; to cavil; to censure words or actions
      without reason or ill-naturedly; -- usually followed by
      at.
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            Carping and caviling at faults of manner. --Blackw.
                                                  Mag.
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            And at my actions carp or catch.      --Herbert.
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The Collaborative International Dictionary of English v.0.48:

Carping \Carp"ing\ (k[aum]rp"[i^]ng), a.
   Fault-finding; censorious caviling. See Captious. --
   Carp"ing*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

carping
    n 1: persistent petty and unjustified criticism [syn:
         faultfinding, carping]