street girl vs fancy woman

street girl and fancy woman both are nouns.

Word	Noun	Adjective	Verb	Adverb
street girl	Yes	No	No	No
fancy woman	Yes	No	No	No

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

street girl (noun)	fancy woman (noun)
a prostitute who attracts customers by walking the streets	an adulterous woman; a woman who has an ongoing extramarital sexual relationship with a man
	a woman who engages in sexual intercourse for money