slur vs utter

slur is a noun but utter is not a noun.

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

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

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

slur (noun)	utter (noun)
a blemish made by dirt
a disparaging remark
(music) a curved line spanning notes that are to be played legato

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

slur (verb)	utter (verb)
become vague or indistinct	express in speech
utter indistinctly	articulate; either verbally or with a cry, shout, or noise
speak disparagingly of; e.g., make a racial slur	express audibly; utter sounds (not necessarily words)
play smoothly or legato	put into circulation