suppositive adjective 1noun 1forms 3 adjective1 •Including or implying supposition, or hypothesis; supposed.Not out of suppositiue coniectures, but out of Alfricus Grammer. — 1605 noun1 •A word denoting or implying supposition.The words "if", "granting", and "provided" are suppositives. formssuppositives · more suppositive · most suppositive