Voluminous rhymes with:
luminous, bituminous, luminous, bituminous, luminous, ominous, androgynous, asynchronous, bituminous, brazenness, chitinous, deaconess, exogenous, gelatinous, givenness, gluttonous, homogenous, indigenous, larcenous, luminous, membranous, monotonous, mountainous, mutinous, nitrogenous, nonpoisonous, oleaginous, ominous, outspokenness, patroness, poisonous, polygynous, ravenous, ruinous, tetanus, titinus, uranus, villainous
Voluminous sounds like:
valence, valencia, valencia's, valens, valenza, vallance, valuing, veiling, villainous, villains, villines, vilnius, violence, violins, volume's, volumes