This meaning refers to a strong working animal usually born from a male donkey and a female horse.
The mule carried supplies up the mountain.
Mules are known for strength and endurance.
This informal crime-related meaning refers to someone used to transport drugs, stolen money, or illegal goods.
The gang used a mule to carry the package.
Customs officers arrested several money mules.
This figurative use compares a stubborn person to the animal's reputation for refusing to move.
He can be as stubborn as a mule.
The old manager was a mule about changing the rules.
