The Collaborative International Dictionary of English v.0.48:

Coyness \Coy"ness\, n.
   The quality of being coy; feigned o? bashful unwillingness to
   become familiar; reserve.
   [1913 Webster]

         When the kind nymph would coyness feign,
         And hides but to be found again.         --Dryden.

   Syn: Reserve; shrinking; shyness; backwardness; modesty;
        bashfulness.
        [1913 Webster]

WordNet (r) 3.0 (2006):

coyness
    n 1: the affectation of being demure in a provocative way [syn:
         coyness, demureness]