Primus rhymes with:
imus, amos, animous, animus, anonymous, artemus, autonomous, bemis, blasphemous, brademas, cadmus, christmas, christmas', clackamas, deltadromeus, demas, demus, dermis, domas, enormous, epidermis, erasmus, famous, grimace, hippopotamus, humus, ignoramus, imus, infamous, isthmus, lemus, litmus, los-palmas, lummus, magnanimous, mandamus, mcamis, mccomas, monogamous, nostradamus, paramus, paulhamus, polhemus, polygamous, posthumous, promise, promus, pumice, pusillanimous, ramus, remus, seamus, shamas, shamus, st_thomas, synonymous, thalamus, thermos, thomas, trimas, ulmus, unanimous, varmus, venomous, warmus
Primus sounds like:
pairing, papering, papernick, papier-mache, paramax, paramus, paranoiac, paring, parnassus, parnes, parness, peering, peppering, permanence, pernice, pernicious, perrins, pharaonic, pharmacia, pharmacies, pharmacy, pharynx, pheromones, poring, pouring, powering, prance, prances, prange, prank, pranks, prawns, praying, prearrange, prearranges, preeminence, preening, premise, premises, premiums, prensa, preying, priam's, primack, primacy, prime's, primeaux, primeco, primenews, primes, priming, primo's, prince, prince's, princes, princess, princess', princess's, princesses, pring, prinkey, prinos, prins, prinz, prinz's, prominence, prominences, promiscuous, promise, promises, promos, proms, promus, prong, prongs, pronounce, pronounces, pronouns, prunes, pruning, prying, purring, pyrenees, pyrenees'