dirty vs blemish

dirty is not a noun while blemish is a noun.

Word	Noun	Adjective	Verb	Adverb
dirty	No	Yes	Yes	No
blemish	Yes	No	Yes	No

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

Other hyponyms of dirty include foul, contaminate, foul, pollute, smear, slime, muddy, muddy up, splash, mire, muck, muck up, mud, crock, spot.

dirty (noun)	blemish (noun)
	a mark or flaw that spoils the appearance of something (especially on a person's body)

dirty (adjective)	blemish (adjective)
soiled or likely to soil with dirt or grime
(of behavior or especially language) characterized by obscenity or indecency
spreading pollution or contamination; especially radioactive contamination
unethical or dishonest
expressing or revealing hostility or dislike
obtained illegally or by improper means
(of a manuscript) defaced with changes
(of color) discolored by impurities; not bright and clear
vile; despicable
contaminated with infecting organisms
unpleasantly stormy
violating accepted standards or rules

dirty (verb)	blemish (verb)
make soiled, filthy, or dirty	add a flaw or blemish to; make imperfect or defective
	mar or impair with a flaw
	mar or spoil the appearance of