stumbler vs blunderer

stumbler and blunderer both are nouns.

Word	Noun	Adjective	Verb	Adverb
stumbler	Yes	No	No	No
blunderer	Yes	No	No	No

As nouns, stumbler and blunderer are synonyms defined as:

stumbler and blunderer: someone who makes mistakes because of incompetence

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

stumbler (noun)	blunderer (noun)
a walker or runner who trips and almost falls	someone who makes mistakes because of incompetence
someone who makes mistakes because of incompetence