disbelieve [ verb ] reject as false; refuse to accept <verb.cognition>discredit
Disbelieve \Dis`be*lieve"\, v. t. [imp. & p. p. {Disbelieved}; p. pr. & vb. n. {Disbelieving}.] Not to believe; to refuse belief or credence to; to hold not to be true or actual.
Assertions for which there is abundant positive evidence are often disbelieved, on account of what is called their improbability or impossibility. --J. S. Mill.