street girl vs streetwalker

street girl and streetwalker both are nouns.

Word	Noun	Adjective	Verb	Adverb
street girl	Yes	No	No	No
streetwalker	Yes	No	No	No

As nouns, street girl and streetwalker are synonyms defined as:

street girl and streetwalker: a prostitute who attracts customers by walking the streets

Other synonyms of street girl include floozie, floozy, hooker, hustler, slattern.

street girl (noun)	streetwalker (noun)
a prostitute who attracts customers by walking the streets	a prostitute who attracts customers by walking the streets