mother figure vs woman

mother figure and woman both are nouns.

Word	Noun	Adjective	Verb	Adverb
mother figure	Yes	No	No	No
woman	Yes	No	No	No

As nouns, woman is a hypernym of mother figure; that is, woman is a word with a broader meaning than mother figure:

mother figure: a woman who evokes the feelings usually reserved for a mother
woman: an adult female person (as opposed to a man)

Other hypernyms of mother figure include adult female.

mother figure (noun)	woman (noun)
a woman who evokes the feelings usually reserved for a mother	women as a class
	an adult female person (as opposed to a man)
	a female person who plays a significant role (wife or mistress or girlfriend) in the life of a particular man