The definition of an adjective is a part of speech that is used to describe a noun. Red, tall, better and fast are all examples of adjectives.
In modern parlance, a gentleman (from gentle + man, translating the Old French gentilz hom) is any man of good, courteous conduct. A gentleman may also simply be a polite term for any man, as in indications of gender-separated facilities, or as a sign of the speaker's own courtesy when addressing others. The modern female equivalent is lady.
1. a. a respectful or formal term of address used to a man: No, sir. b. a formal term of address used in the salutation of a letter. 2. (cap.) the distinctive title of a knight or baronet: Sir Walter Scott. 3. a lord or gentleman: noble sirs and ladies.