wow vs howler

wow and howler both are nouns.

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

As nouns, wow and howler are synonyms defined as:

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

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

wow (verb)	howler (verb)
impress greatly