Fissionable rhymes with:
actionable, fashionable, impressionable, objectionable, unconscionable, unfashionable, unmentionable, abominable, actionable, determinable, fashionable, imaginable, impressionable, inalienable, interminable, objectionable, personable, questionable, reasonable, seasonable, terminable, unconscionable, unfashionable, unmentionable, unquestionable