Dimunition rhymes with:
munition, munition, munition, admonition, ammunition, clinician, cognition, daffynition, definition, ignition, misrecognition, munition, preignition, premonition, recognition, redefinition, technician
Dimunition sounds like:
damnation, dandeneau, dantin, danton, dantoni, dantonio, dantuono, demotion, denden, denomination, dentin, dentine, dentino, dentition, denton, dentton, detention, detonation, diantonio, diminution, domination, donathan, donation, downtime, downtown, dundon, dunedin, dunton