* Literal: The mule stubbornly refused to move, its ears twitching in annoyance.
* Figurative: The spy was a mule for the enemy, smuggling secrets across the border.
* Idiom: He's a mule when it comes to listening to advice.
* Slang: She's got a mule kick, that girl! (meaning she has a lot of energy and can move quickly).
The word "mule" can have different meanings depending on the context. It's important to consider the intended meaning when using it.