fumble vs flub

fumble and flub both are nouns.

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

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

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

As verbs, fumble and flub are synonyms defined as:

fumble (noun)	flub (noun)
(sports) dropping the ball	an embarrassing mistake

fumble (verb)	flub (verb)
drop or juggle or fail to play cleanly a grounder	make a mess of, destroy or ruin
feel about uncertainly or blindly
handle clumsily
make one's way clumsily or blindly
make a mess of, destroy or ruin