* Noun: This is the most common use. It refers to a person who actively opposes or is hostile to someone or something.
* Example: "The villain was the main antagonist in the story."
* Adjective: It can describe something that is opposing or hostile.
* Example: "The antagonist forces were defeated in the battle."
* Verb: It can be used as a verb, meaning to oppose or act against someone or something.
* Example: "The government antagonized the protesters."
So, to determine the part of speech, you need to look at the sentence it's used in.