I. adjective 1. relating to or denoting reasoning or knowledge which proceeds from observations or experiences to the deduction of probable causes. 2. (in general use) of the nature of an afterthought or subsequent rationalization. II. adverb 1. in a way based on reasoning from known facts or past events rather than by making assumptions or predictions. 2. [ sentence adverb] — with hindsight; as an afterthought.
– origin early 17th cent.: Latin, ‘from what comes after’.