gentlewoman vs madam

gentlewoman and madam both are nouns.

Word	Noun	Adjective	Verb	Adverb
gentlewoman	Yes	No	No	No
madam	Yes	No	No	No

As nouns, gentlewoman and madam are synonyms defined as:

Other synonyms of gentlewoman include dame, lady, ma'am.

gentlewoman (noun)	madam (noun)
a woman of refinement	a woman of refinement
	a woman who runs a house of prostitution