Here's what rhymes with antigrammatical.
grammatical ungrammatical Words that almost rhyme with antigrammatical
radical national practical rational casual compatible maximal adaptable mandible clavicle fallible palatal cannibal laughable passable cantonal unpractical chasuble cantabile satiable savable capital valuable tangible diagonal irrational palpable taxable impassable impractical infallible pyramidal factional lnternational octagonal sagittal tractable flammable merchantable blamable impassible bankable attractable fanciable international incompatible invaluable transnational fractional implacable intangible intractable inflammable supranational transactional impalpable verapamil collapsible nontaxable retractable graspable unflappable frangible multinational hexagonal interactional detachable semiannual nonflammable declarable understandable extrapyramidal expandable nondetachable