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.
In the United States, the term gentlemen's club is commonly used to refer euphemistically to strip clubs. As a result, traditional gentlemen's clubs often are referred to as men's clubs or city clubs (as opposed to country clubs) or simply as private social clubs or just private clubs.