Sentence examples for a bad guy from inspiring English sources

The phrase "a bad guy" is correct and usable in written English.
It can be used to refer to someone who is perceived as evil or morally wrong, often in the context of storytelling, movies, or discussions about behavior.
Example: "In the movie, the protagonist must confront a bad guy who threatens the safety of the entire city."
Alternatives: "an antagonist" or "a villain".