blotch vs slur

blotch and slur both are nouns.

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

As nouns, slur is a hypernym of blotch; that is, slur is a word with a broader meaning than blotch:

Other hypernyms of blotch include blot, daub, smear, smirch, smudge, spot.

blotch (noun)	slur (noun)
an irregularly shaped spot	a blemish made by dirt
	a disparaging remark
	(music) a curved line spanning notes that are to be played legato

blotch (verb)	slur (verb)
mark with spots or blotches of different color or shades of color as if stained	become vague or indistinct
	utter indistinctly
	speak disparagingly of; e.g., make a racial slur
	play smoothly or legato