Formal:
* 厕所 (cèsuǒ): This is the most common and neutral term for "toilet". It can be used in most situations.
Informal:
* 洗手间 (xǐshǒujiān): This literally means "hand-washing room" and is more common in public places like restaurants and shops.
* 卫生间 (wèishēngjiān): This literally means "hygiene room" and can be used in more formal settings.
* 茅厕 (máo cè): This is a more traditional term for "toilet" and is considered old-fashioned.
* 便所 (biànsuǒ): This is another traditional term for "toilet" and is not commonly used anymore.
Slang:
* 茅坑 (máo kēng): This is a slang term for "toilet" and is considered vulgar.
It's best to use 厕所 (cèsuǒ) unless you are in a very specific situation where another term is more appropriate.