Definition
to make something rough or rougher
How People Actually Use It
In a strict sense, the object being descibed has been subject to physical violence. When used as a slang term, the implication is that the said object is undesirable or otherwise crippled.
"Strict: The police roughed up a criminal on drugs before arresting him. Slang: "John's car is roughed up." This would imply that John's car has many undesirable qualities, eg. old, worn, broken, etc Slang: If your grandmother cooked you a birthday cake and it looked like a lump of sand, you might say that cake is roughed up."
Source: Urban Dictionary