Here's what rhymes with serendipitous.
precipitous Words that almost rhyme with serendipitous
siliceous spirituous spiritless piggishness willingness ubiquitous fierceness iniquitous duplicitous priggishness implicitness derisiveness griminess jinrickshas jinrikshas filminess certificates permissiveness significance litigants submissiveness vindictiveness explicitness restrictiveness cliquishness skittishness coincidence descriptiveness distinctiveness insignificance