Entry 2 senses · 2 variants Webster, 1913 Suppositive · Sup·pos·i·tive · IPA a. n. 01 a. Including or implying supposition, or hypothesis; supposed. 1. Including or implying supposition, or hypothesis; supposed. 02 n. A word denoting or implying supposition, as the words if, granting, provided, etc. 1. A word denoting or implying supposition, as the words if, granting, provided, etc.