smudge vs blemish

smudge and blemish both are nouns.

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

As nouns, blemish is a hypernym of smudge; that is, blemish is a word with a broader meaning than smudge:

smudge: a blemish made by dirt
blemish: a mark or flaw that spoils the appearance of something (especially on a person's body)

Other hypernyms of smudge include defect, mar.

smudge (noun)	blemish (noun)
a blemish made by dirt	a mark or flaw that spoils the appearance of something (especially on a person's body)
a smoky fire to drive away insects

smudge (verb)	blemish (verb)
make a smudge on; soil by smudging	add a flaw or blemish to; make imperfect or defective
	mar or impair with a flaw
	mar or spoil the appearance of