Here's what rhymes with unauthoritative.
dative native authoritative qualitative imitative iterative oxidative vegetative radiative connotative annotative creative innovative educative meditative dissipative copulative nonnative cogitative emulative cooperative legislative collaborative appreciative associative evaluative deliberative evaporative regulative denotative stimulative quantitative integrative interpretative manipulative dissociative rehabilitative accumulative procreative investigative unappreciative administrative nonadministrative Words that almost rhyme with unauthoritative
cages sages rages mutatis phages wadis wadges engages bellyaches reengages macrophages disengages greengages abrasive plaintive pervasive evasive invasive persuasive dissuasive nonabrasive unpersuasive noninvasive