Here's what rhymes with mantissas.
Words that almost rhyme with mantissas
animus activeness mannishness massiveness amirates applicants managements lavishness passiveness clannishness caddishness faddishness snappishness waggishness harelips raffishness draughtiness laddishness rabidness attractiveness combativeness impassiveness brackishness expansiveness outlandishness gallivants blandishments establishments