farm girl vs girl

farm girl and girl both are nouns.

Word	Noun	Adjective	Verb	Adverb
farm girl	Yes	No	No	No
girl	Yes	No	No	No

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

Other hypernyms of farm girl include female child, little girl.

farm girl (noun)	girl (noun)
a girl who has grown up on a farm	a young female
	a girl or young woman with whom a man is romantically involved
	a youthful female person
	a friendly informal reference to a grown woman
	a female human offspring