Here's what rhymes with insubstantive.
Words that almost rhyme with insubstantive
punches lunches plunges hunches lunges brunches munches crunches lumpish expunges frumpish scrunches keypunches muskellunges obstructive seductive irruptive destructive productive inductive disruptive subjunctive ablative disjunctive eruptive vocative appositive constructive instructive impulsive repulsive unproductive conductive locative fricative propulsive assumptive mutative combustive lenitive reproductive compulsive transitive convulsive presumptive consumptive nondestructive nonproductive counterproductive proliferative reconstructive superconductive nonconstructive