Definition from Wiktionary, the free dictionary
factive (not comparable)
- (linguistics, of a verb) Licensing only those content clauses that represent claims assumed to be true.
- You can't say he "discovered" that the moon is made of green cheese, because "discover" is a factive verb and the moon isn't made of green cheese.
- (epistemology, of a knowing agent) which does not know any falsities: which knows only truths.