Assiduous rhymes with:
fatuous, impetuous, incestuous, inconspicuous, marquess, presumptuous, promiscuous, sensuous, sinuous, sumptuous, tenuous, tortuous, unambiguous, unctuous, voluptuous
Assiduous sounds like:
accedes, acetic, achatz, acidic, acidosis, acids, acoustic, acoustics, acquits, act's, acts, actus, aesthete's, aesthetes, aesthetic, aesthetics, agates, akita's, aquatic, ascetic, ashtec, ashtec's, asiatic, asides, assad's, assets, assets', assists, associate's, associates, associates', august's, augusta's, augustus, auschwitz, azides, aztec, azteca, aztecs