* Rude: This is a general antonym for courteous, meaning lacking in manners or respect.
* Discourteous: This is a more formal antonym, meaning lacking in politeness or consideration.
* Impolite: Similar to rude, but with a slightly less harsh connotation.
* Insolent: This implies a bolder and more disrespectful form of rudeness.
* Uncivil: This emphasizes a lack of good manners and respect for social norms.
* Boorish: This implies a crude and insensitive manner.
* Unmannerly: This emphasizes a lack of good manners and etiquette.
* Disrespectful: This focuses on the lack of respect shown to others.
The best antonym for "courteous" will depend on the specific situation and the intended meaning.