blurt out vs blunder

blurt out is not a noun while blunder is a noun.

Word	Noun	Adjective	Verb	Adverb
blurt out	No	No	Yes	No
blunder	Yes	No	Yes	No

As verbs, blurt out and blunder are synonyms defined as:

Other synonyms of blurt out include blunder out, blurt, ejaculate.

blurt out (noun)	blunder (noun)
	an embarrassing mistake

blurt out (verb)	blunder (verb)
utter impulsively	utter impulsively
	make one's way clumsily or blindly
	commit a faux pas or a fault or make a serious mistake