Here's what rhymes with fretsome.
jetsam Words that almost rhyme with fretsome
pepsin stepson reception exception perception deception inception conception interception contraception misconception preconception rectum arum seldom spectrum welcome emblem septum venom harem denim plenum vellum velum phenom plectrum cerebellum addendum flagellum bedlam momentum referendum unwelcome interregnum antebellum antiserum