What is the meaning of Qualifier?

One who qualifies for something, especially a contestant who qualifies for a stage in a competition.

A preliminary stage of a competition.

A word or phrase, such as an adjective or adverb, that describes or characterizes another word or phrase, such as a noun or verb; a modifier; that adds or subtracts attributes to another.

A marker that qualifies or modifies another code element.

to qualify (of a sports team, etc.)

(to compete successfully in some stage of a competition and become eligible for the next stage)

to call someone something, to label someone

Source: wiktionary.org