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