[[A factive predicate is a predicate that takes a °complement clause whose truth is presupposed by the speaker.]]
factive event (SEM) = an event in which a positive epistemic stance is taken by the speaker toward a proposition denoted by some part of that construction. Example: It is appalling that Donald won the election – an example of a commentative complement clause construction – is factive in that the speaker takes a positive epistemic stance toward the complement proposition that Donald won the election.