Here's what rhymes with diligendum.
referendum Words that almost rhyme with diligendum
tendon dentin inattention intention momentum distention abstention hempen subvention indention intervention supervention contravention circumvention nonintervention addendum denim seldom venom plenum bedlam jetsam phenom welcome harem flagellum vellum velum webcam spectrum rectum septum cerebellum unwelcome plectrum bubblegum envenom interregnum antebellum antiserum