These words are comparable in that they each denote a chronic tendency or temporary disposition to withhold belief. Unbelief refers to the absence of positive belief, especially the lack of belief in God and any of the religious faiths based on a belief in God. More than the other two words in this group, it suggests a chronic mental quality rather than a particular instance of doubt: the impossibility of trying to harmonize the unbelief of an atheist and the conviction of a Catholic dogmatist. In theological usage, unbelief has condemnatory force, since it implies the wilful rejection of manifest truth.

Disbelief refers to a positive conviction that a particular act, statement, doctrine, etc., is untrue, even in the face of its asserted validity. It hints at an isolated or temporary rejection instead of a continuously doubting state of mind: so committed to his point of view that he dismissed with disbelief all evidence of his error; A look of disbelief replaced the smile on his face.

Incredulity is a disinclination to accept as true whatever has been suggested as such; it is based on skepticism and a disposition to criticize or object. The word indicates a set frame of mind more than does disbelief , but less so than unbelief: extravagant claims for a product that were met with incredulity by knowledgeable buyers.