Portentous rhymes with:
apprentice, momentous, proventus, apprentice, brountas, countess, lintas, momentous, pocahontas, proventus, qantas, santas
Portentous sounds like:
portends, portents, predominates, pretends, pretentious
apprentice, momentous, proventus, apprentice, brountas, countess, lintas, momentous, pocahontas, proventus, qantas, santas
portends, portents, predominates, pretends, pretentious