The Collaborative International Dictionary of English v.0.48:

Nonacceptance \Non`ac*cept"ance\, n.
   A neglect or refusal to accept.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nonacceptance
    n 1: the act of refusing an offer; "the turndown was polite but
         very firm" [syn: nonacceptance, turndown]

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "nonacceptance":
   abjuration, abjurement, abnegation, chucking, chucking out,
   contempt, contradiction, declension, declination, declinature,
   declining, denial, deprivation, despisal, despising, disagreement,
   disallowance, disapproval, discard, disclaimer, disclamation,
   discounting, dismissal, disobedience, disownment, disregard,
   dissent, exception, exclusion, holding back, ignoring, nay,
   negation, negative, negative answer, nix, no, nonapproval,
   noncompliance, nonconsent, nonconsideration, nonobservance,
   passing by, putting away, putting out, rebuff, recantation,
   refusal, rejection, renouncement, repudiation, repulse, retention,
   scouting, spurning, throwing out, thumbs-down, turndown,
   turning out, unwillingness, withholding