girl Friday vs woman

girl Friday and woman both are nouns.

Word	Noun	Adjective	Verb	Adverb
girl Friday	Yes	No	No	No
woman	Yes	No	No	No

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

Other hypernyms of girl Friday include assistant, help, helper, supporter, adult female.

girl Friday (noun)	woman (noun)
a female assistant who has a range of duties	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