Source : Webster's Revised Unabridged Dictionary (1913)

Disbelief \Dis*be*lief"\, n.
   The act of disbelieving;; a state of the mind in which one is
   fully persuaded that an opinion, assertion, or doctrine is
   not true; refusal of assent, credit, or credence; denial of
   belief.

         Our belief or disbelief of a thing does not alter the
         nature of the thing.                     --Tillotson.

         No sadder proof can be given by a man of his own
         littleness that disbelief in great men.  --Carlyle.

   Syn: Distrust; unbelief; incredulity; doubt; skepticism. --
        {Disbelief}, {Unbelief}. Unbelief is a mere failure to
        admit; disbelief is a positive rejection. One may be an
        unbeliever in Christianity from ignorance or want of
        inquiry; a unbeliever has the proofs before him, and
        incurs the guilt of setting them aside. Unbelief is
        usually open to conviction; disbelief is already
        convinced as to the falsity of that which it rejects.
        Men often tell a story in such a manner that we regard
        everything they say with unbelief. Familiarity with the
        worst parts of human nature often leads us into a
        disbelief in many good qualities which really exist
        among men.

Source : WordNet®

disbelief
     n 1: doubt about the truth of something [syn: {incredulity}, {skepticism},
           {mental rejection}]
     2: a rejection of belief [syn: {unbelief}] [ant: {belief}]