Here's what rhymes with definion.
pinyon Words that almost rhyme with definion
fireman firemen heighten siren hyphen scion siphon hymen syphon lineman linemen finespun horizon lion fibrin frighten tighten widen bison lichen lighten ripen beiden liken whiten liven thriven titan linesman billycan enlighten brighten enliven baryon prion veniremen bedizen funnyman aphelion cotyledon perihelion dicotyledon dandelion monocotyledon