bar girl vs B-girl

bar girl and B-girl both are nouns.

Word	Noun	Adjective	Verb	Adverb
bar girl	Yes	No	No	No
B-girl	Yes	No	No	No

As nouns, bar girl and B-girl are synonyms defined as:

bar girl and B-girl: a woman employed by a bar to act as a companion to men customers

bar girl (noun)	B-girl (noun)
a woman employed by a bar to act as a companion to men customers	a woman employed by a bar to act as a companion to men customers