blur vs muddy

blur is a noun but muddy is not a noun.

Word	Noun	Adjective	Verb	Adverb
blur	Yes	No	Yes	No
muddy	No	Yes	Yes	No

As verbs, muddy is a hyponym of blur; that is, muddy is a word with a more specific, narrower meaning than blur:

blur (noun)	muddy (noun)
a hazy or indistinct representation

blur (adjective)	muddy (adjective)
	dirty and messy; covered with mud or muck
	(of color) discolored by impurities; not bright and clear
	(of liquids) clouded as with sediment
	(of soil) soft and watery

blur (verb)	muddy (verb)
become vague or indistinct	make turbid
make dim or indistinct	cause to become muddy
make unclear, indistinct, or blurred	dirty with mud
make a smudge on; soil by smudging
to make less distinct or clear
become glassy; lose clear vision