sexism vs favouritism

sexism and favouritism both are nouns.

Word	Noun	Adjective	Verb	Adverb
sexism	Yes	No	No	No
favouritism	Yes	No	No	No

As nouns, favouritism is a hypernym of sexism; that is, favouritism is a word with a broader meaning than sexism:

sexism: discriminatory or abusive behavior towards members of the opposite sex
favouritism: unfair treatment of a person or group on the basis of prejudice

Other hypernyms of sexism include discrimination, favoritism.

sexism (noun)	favouritism (noun)
discriminatory or abusive behavior towards members of the opposite sex	unfair treatment of a person or group on the basis of prejudice
	an inclination to favor some person or group