illative /ɪˈleɪtɪv/noun 3adjective 2forms 1 noun3 •The illative case, or a word in that case. •A word or phrase that expresses an inference (such as for or therefore). •An illation. adjective2 •Of, or relating to the grammatical case that in some languages indicates motion towards or into something. •Of, or relating to an illation. formsillatives