ethnic slur vs slur

ethnic slur and slur both are nouns.

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

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

Other hypernyms of ethnic slur include aspersion.

ethnic slur (noun)	slur (noun)
a slur on someone's race or language	a blemish made by dirt
	a disparaging remark
	(music) a curved line spanning notes that are to be played legato

ethnic slur (verb)	slur (verb)
	become vague or indistinct
	utter indistinctly
	speak disparagingly of; e.g., make a racial slur
	play smoothly or legato