As nouns the difference between gallant and courage
is that
gallant is (dated) fashionable young man, who is polite and attentive to women while
courage is courage.
As an adjective gallant
is brave, valiant or
gallant can be polite and attentive to ladies; courteous to women; chivalrous.
As a verb gallant
is (obsolete|transitive) to attend or wait on (a lady).