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.
Definition of sir. 1  1a : a man entitled to be addressed as sir âused as a title before the given name of a knight or baronet and formerly sometimes before the given name of a priestb : a man of rank or position. 2  2a âused as a usually respectful form of addressb capitalized âused as a conventional form of address in the salutation of a letter.