Source : Webster's Revised Unabridged Dictionary (1913)

Unbelief \Un`be*lief"\, n. [Pref. un- not + belief: cf. AS.
   ungele['a]fa.]
   1. The withholding of belief; doubt; incredulity; skepticism.

   2. Disbelief; especially, disbelief of divine revelation, or
      in a divine providence or scheme of redemption.

            Blind unbelief is sure to err, And scan his work in
            vain.                                 --Cowper.

   Syn: See {Disbelief}.

Source : WordNet®

unbelief
     n : a rejection of belief [syn: {disbelief}] [ant: {belief}]