thigh-slapper vs sidesplitter

thigh-slapper and sidesplitter both are nouns.

Word	Noun	Adjective	Verb	Adverb
thigh-slapper	Yes	No	No	No
sidesplitter	Yes	No	No	No

As nouns, thigh-slapper and sidesplitter are synonyms defined as:

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

thigh-slapper (noun)	sidesplitter (noun)
a joke that seems extremely funny	a joke that seems extremely funny