Oxford Dictionary
side-splitting
side-splitting ▶adjective informal extremely amusing: side-splitting anecdotes. DERIVATIVES side-splittingly adverb
American Oxford Thesaurus
side-splitting
side-splitting adjective informal See hilarious.
Oxford Thesaurus
side-splitting
side-splitting adjective informal side-splitting anecdotes: hilarious, extremely amusing, very funny, very humorous, comic, riotous, uproarious, screamingly /hysterically funny, too funny for words, rib-tickling, comical, absurd, ridiculous; informal a scream, a hoot, priceless; dated killing, killingly funny.