blot vs blemish

blot and blemish both are nouns.

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

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

blot: 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 blot include defect, mar.

blot (noun)	blemish (noun)
an act that brings discredit to the person who does it	a mark or flaw that spoils the appearance of something (especially on a person's body)
a blemish made by dirt

blot (verb)	blemish (verb)
dry (ink) with blotting paper	add a flaw or blemish to; make imperfect or defective
make a spot or mark onto	mar or impair with a flaw
	mar or spoil the appearance of