fumbler vs bumbler

fumbler and bumbler both are nouns.

Word	Noun	Adjective	Verb	Adverb
fumbler	Yes	No	No	No
bumbler	Yes	No	No	No

As nouns, fumbler and bumbler are synonyms defined as:

Other synonyms of fumbler include blunderer, botcher, bungler, butcher, fuckup, sad sack, stumbler.

fumbler (noun)	bumbler (noun)
someone who makes mistakes because of incompetence	someone who makes mistakes because of incompetence