What is the name for a wild mustang in western US?

There isn't a specific name for a wild mustang in the western US, as "mustang" itself refers to any wild horse descended from domestic horses brought to the Americas by Spanish conquistadors.

You can use terms like:

* Wild horse: This is the most common and accurate term.

* Feral horse: This emphasizes their wild nature and lack of domestication.

* Free-roaming horse: This highlights their freedom and lack of human control.

It's important to note that "mustang" is sometimes used interchangeably with "wild horse" but technically refers to the horse's origin rather than its current status.