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