bellow vs utter

bellow is a noun but utter is not a noun.

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

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

Other hypernyms of bellow include emit, let loose, let out.

bellow (noun)	utter (noun)
a very loud utterance (like the sound of an animal)

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

bellow (verb)	utter (verb)
shout loudly and without restraint	express in speech
make a loud noise, as of animal	articulate; either verbally or with a cry, shout, or noise
	express audibly; utter sounds (not necessarily words)
	put into circulation