[syn: unbelief, disbelief]
The Collaborative International Dictionary of English v.0.48:
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.
   [1913 Webster]
         Our belief or disbelief of a thing does not alter the
         nature of the thing.                     --Tillotson.
   [1913 Webster]
         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.
        [1913 Webster]
WordNet (r) 3.0 (2006):
disbelief
    n 1: doubt about the truth of something [syn: incredulity,
         disbelief, skepticism, mental rejection]
    2: a rejection of belief [syn: unbelief, disbelief] [ant:
       belief]
Moby Thesaurus II by Grady Ward, 1.0:
32 Moby Thesaurus words for "disbelief":
   agnosticism, atheism, confutability, contestability,
   controvertibility, deism, deniability, denial, discredit,
   disputability, doubt, doubtfulness, dubiety, dubiousness,
   dubitancy, faithlessness, heresy, inability to believe,
   incredulity, infidelity, minimifidianism, misbelief, nonbelief,
   nullifidianism, questionableness, refutability, rejection,
   repudiation, secularism, spurning, unbelief, unbelievingness