smirch vs slur

smirch and slur both are nouns.

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

As nouns, smirch and slur are synonyms defined as:

Other synonyms of smirch include blot, daub, smear, smudge, spot.

smirch (noun)	slur (noun)
an act that brings discredit to the person who does it	a blemish made by dirt
a blemish made by dirt	a disparaging remark
	(music) a curved line spanning notes that are to be played legato

smirch (verb)	slur (verb)
charge falsely or with malicious intent; attack the good name and reputation of someone	become vague or indistinct
smear so as to make dirty or stained	utter indistinctly
	speak disparagingly of; e.g., make a racial slur
	play smoothly or legato