The Collaborative International Dictionary of English v.0.48:

Complacence \Com*pla"cence\, Complacency \Com*pla"cen*cy\, n.
   [LL. complacentia: cf. F. complaisance. See Complacent, and
   cf. Complaisance.]
   1. Calm contentment; satisfaction; gratification.
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            The inward complacence we find in acting reasonably
            and virtuously.                       --Atterbury.
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            Others proclaim the infirmities of a great man with
            satisfaction and complacency, if they discover none
            of the like in themselves.            --Addison.
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   2. The cause of pleasure or joy. "O thou, my sole
      complacence." --Milton.
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   3. The manifestation of contentment or satisfaction; good
      nature; kindness; civility; affability.
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            Complacency, and truth, and manly sweetness,
            Dwell ever on his tongue, and smooth his thoughts.
                                                  --Addison.
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            With mean complacence ne'er betray your trust.
                                                  --Pope.
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WordNet (r) 3.0 (2006):

complacency
    n 1: the feeling you have when you are satisfied with yourself;
         "his complacency was absolutely disgusting" [syn:
         complacency, complacence, self-complacency, self-
         satisfaction]