blurt vs utter

blurt is not an adjective while utter is an adjective.

Word	Noun	Adjective	Verb	Adverb
blurt	No	No	Yes	No
utter	No	Yes	Yes	No

As verbs, utter is a hypernym of blurt; that is, utter is a word with a broader meaning than blurt:

Other hypernyms of blurt include mouth, speak, talk, verbalise, verbalize.

blurt (adjective)	utter (adjective)
	complete and absolute
	without qualification; used informally as (often pejorative) intensifiers

blurt (verb)	utter (verb)
utter impulsively	express in speech
	articulate; either verbally or with a cry, shout, or noise
	express audibly; utter sounds (not necessarily words)
	put into circulation