1.(Logic) Direct; proving directly; applied to reasoning, and opposed to elenchtic or refutative.
2.(Grammar) Showing or pointing to directly; pertaining to deixis; used to designate words that specify identity, location, or time from the perspective of one of the participants in a discourse, using the surrounding context as reference; as, the words this, that, these, those, here, there, now, then, we, you, they, the former, and the latter serve a deictic function.