mama vs mammy

mama and mammy both are nouns.

Word	Noun	Adjective	Verb	Adverb
mama	Yes	No	No	No
mammy	Yes	No	No	No

As nouns, mama and mammy are synonyms defined as:

Other synonyms of mama include ma, mamma, mom, momma, mommy, mum, mumma, mummy.

mama (noun)	mammy (noun)
informal terms for a mother	informal terms for a mother
	an offensive term for a Black nursemaid in the southern U.S.