howler vs sidesplitter

howler and sidesplitter both are nouns.

Word	Noun	Adjective	Verb	Adverb
howler	Yes	No	No	No
sidesplitter	Yes	No	No	No

As nouns, howler and sidesplitter are synonyms defined as:

Other synonyms of howler include belly laugh, riot, scream, thigh-slapper, wow.

howler (noun)	sidesplitter (noun)
a glaring blunder	a joke that seems extremely funny
monkey of tropical South American forests having a loud howling cry
a joke that seems extremely funny