DISBELIEVING
disbelieving, skeptical, sceptical, unbelieving
(adjective) denying or questioning the tenets of especially a religion; “a skeptical approach to the nature of miracles”
Source: WordNet® 3.1
Verb
disbelieving
present participle of disbelieve
Adjective
disbelieving (comparative more disbelieving, superlative most disbelieving)
refusing to believe; skeptical or incredulous
Source: Wiktionary
DISBELIEVE
Dis`be*lieve", v. t. [imp. & p. p. Disbelieved; p. pr. & vb. n.
Disbelieving.]
Definition: 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.
Source: Webster’s Unabridged Dictionary 1913 Edition