What is a prefix for rough?

There isn't a single, commonly used prefix specifically for "rough". However, depending on the context you're aiming for, you can use prefixes like:

* Rough- (This is the most straightforward option and is frequently used): rough-hewn, rough-textured, rough-and-tumble

* Un- (For emphasizing lack of smoothness): unpolished, unrefined, unkempt

* In- (For emphasizing difficulty or hardship): inhospitable, intractable, inoperable

* Im- (Similar to "in-" for emphasizing difficulty): impervious, impenetrable, impassable

The best prefix will depend on the specific meaning you want to convey.