gallantry vs bravery

gallantry and bravery both are nouns.

Word	Noun	Adjective	Verb	Adverb
gallantry	Yes	No	No	No
bravery	Yes	No	No	No

As nouns, bravery is a hypernym of gallantry; that is, bravery is a word with a broader meaning than gallantry:

gallantry: the qualities of a hero or heroine; exceptional or heroic courage when facing danger (especially in battle)
bravery: a quality of spirit that enables you to face danger or pain without showing fear

Other hypernyms of gallantry include braveness, courage, courageousness.

gallantry (noun)	bravery (noun)
polite attentiveness to women	a quality of spirit that enables you to face danger or pain without showing fear
the qualities of a hero or heroine; exceptional or heroic courage when facing danger (especially in battle)	feeling no fear
courtesy towards women