Source : Webster's Revised Unabridged Dictionary (1913)

Pardon \Pardon\, remission \remission\

   Usage: {Forgiveness}, {Pardon}. Forgiveness is Anglo-Saxon,
          and pardon Norman French, both implying a giving back.
          The word pardon, being early used in our Bible, has,
          in religious matters, the same sense as forgiveness;
          but in the language of common life there is a
          difference between them, such as we often find between
          corresponding Anglo-Saxon and Norman words. Forgive
          points to inward feeling, and suppose alienated
          affection; when we ask forgiveness, we primarily seek
          the removal of anger. Pardon looks more to outward
          things or consequences, and is often applied to
          trifling matters, as when we beg pardon for
          interrupting a man, or for jostling him in a crowd.
          The civil magistrate also grants a pardon, and not
          forgiveness. The two words are, therefore, very
          clearly distinguished from each other in most cases
          which relate to the common concerns of life. Forgiver
\For*giv"er\, n.
   One who forgives. --Johnson.

Source : WordNet®

forgiver
     n : a person who pardons or forgives or excuses a fault or
         offense [syn: {pardoner}, {excuser}]