gallantry vs heroism

gallantry and heroism both are nouns.

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

As nouns, gallantry and heroism are synonyms defined as:

gallantry and heroism: the qualities of a hero or heroine; exceptional or heroic courage when facing danger (especially in battle)

Other synonyms of gallantry include valiance, valiancy, valor, valorousness, valour.

gallantry (noun)	heroism (noun)
polite attentiveness to women	the qualities of a hero or heroine; exceptional or heroic courage when facing danger (especially in battle)
the qualities of a hero or heroine; exceptional or heroic courage when facing danger (especially in battle)
courtesy towards women