grande dame vs gentlewoman

grande dame and gentlewoman both are nouns.

Word	Noun	Adjective	Verb	Adverb
grande dame	Yes	No	No	No
gentlewoman	Yes	No	No	No

As nouns, gentlewoman is a hypernym of grande dame; that is, gentlewoman is a word with a broader meaning than grande dame:

grande dame: a middle-aged or elderly woman who is stylish and highly respected
gentlewoman: a woman of refinement

Other hypernyms of grande dame include dame, lady, ma'am, madam.

grande dame (noun)	gentlewoman (noun)
a middle-aged or elderly woman who is stylish and highly respected	a woman of refinement