Clemency is a pardon or forgiveness of a crime and all relevant penalties. It is usually granted by a head of state such as a monarch or president.
A pardon is the forgiveness of a crime and the cancellation of the relevant penalty; it is usually granted by a head of state (such as a monarch or president) or by acts of a parliament or a religious authority. Clemency means the forgiveness of a crime or the cancellation (in whole or in part) of the penalty associated with it. It is a general concept that encompasses several related procedures: pardoning, commutation, remission and reprieves. Commutation or remission is the lessening of a penalty without forgiveness for the crime; the beneficiary is still considered guilty of the offense. A reprieve is the temporary postponement of punishment, often with a view to a pardon or other review of the sentence (such as when the reprieving authority has no power to grant an immediate pardon). Today, pardons are granted in many countries when individuals have demonstrated that they have fulfilled their debt to society, or are otherwise considered to be deserving.
Contributions by CliffC, 184.108.40.206, and Ellsworth.