howler vs flub

howler and flub both are nouns.

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

As nouns, flub is a hypernym of howler; that is, flub is a word with a broader meaning than howler:

Other hypernyms of howler include bloomer, blooper, blunder, boner, boo-boo, botch, bungle, foul-up, fuckup, pratfall.

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

howler (verb)	flub (verb)
	make a mess of, destroy or ruin