blunder out vs blunder

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

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

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

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

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

blunder 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