slut vs working girl

slut and working girl both are nouns.

Word	Noun	Adjective	Verb	Adverb
slut	Yes	No	No	No
working girl	Yes	No	No	No

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

slut (noun)	working girl (noun)
a woman adulterer	a young woman who is employed
a dirty untidy woman	a woman who engages in sexual intercourse for money
A sexually loose woman