The Collaborative International Dictionary of English v.0.48:

Connivance \Con*niv"ance\, n. [Cf. F. connivence, L.
   conniventia.]
   1. Intentional failure or forbearance to discover a fault or
      wrongdoing; voluntary oversight; passive consent or
      cooperation.
      [1913 Webster]

   2. (Law) Corrupt or guilty assent to wrongdoing, not
      involving actual participation in, but knowledge of, and
      failure to prevent or oppose it.

   Syn: See Collusion.
        [1913 Webster]

WordNet (r) 3.0 (2006):

connivance
    n 1: agreement on a secret plot [syn: connivance, collusion]
    2: (law) tacit approval of someone's wrongdoing [syn:
       connivance, secret approval, tacit consent]