Here's what rhymes with proficuous.
congruous exiguous Words that almost rhyme with proficuous
lupus clueless lulus units useless mucous mucus ruthless acuteness cubits eunuchs humus newness rudeness fluence blueness crudeness lewdness roofless rootless cuteness glumness cutups ulnas chukkas houmous houmus fruitless nuisance prudence coolness shrewdness aloofness hubris toothless tulips moonless bootless caduceus muteness truants juleps mullets gullets glamourous tuneups mutants persecutions pursuance smoothness tumults astuteness avoirdupois obtuseness scrofulous resoluteness canoeists coolants duellists humourless intuits profuseness sublets spruceness hirsuteness bouffants students movements jurisprudence amusements foodstuffs pollutants imprudence impudence absoluteness diffuseness dissoluteness annuitants translucence abstruseness irresoluteness manumits quadruplets improvements inducements disputants