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