slur vs smirch

slur and smirch both are nouns.

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

As nouns, slur and smirch are synonyms defined as:

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

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

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