mother's boy vs mama's boy

mother's boy and mama's boy both are nouns.

Word	Noun	Adjective	Verb	Adverb
mother's boy	Yes	No	No	No
mama's boy	Yes	No	No	No

As nouns, mother's boy and mama's boy are synonyms defined as:

mother's boy and mama's boy: a boy excessively attached to his mother; lacking normal masculine interests

Other synonyms of mother's boy include mamma's boy.

mother's boy (noun)	mama's boy (noun)
a boy excessively attached to his mother; lacking normal masculine interests	a boy excessively attached to his mother; lacking normal masculine interests