A more thorough explanation:

Definition: Incommutable means that an offense cannot be changed or replaced. It is the opposite of commutable.

Example: In criminal law, if a severe punishment has already been given to a defendant, the executive may substitute it with a less severe punishment. This is called commutation. However, if the offense is incommutable, it cannot be changed or replaced.

Explanation: The example illustrates that incommutable offenses cannot be changed or replaced, even by the executive. It is a fixed punishment that cannot be altered. This term is commonly used in criminal law, but it can also be used in other areas such as commercial and civil law.