(historical) In medieval Catholicism, a person licensed to grant papal pardons or indulgences.
1917, Catholic Encyclopedia, "Collections" http://www.newadvent.org/cathen/04104b.htm
These grants of Indulgence were often entrusted to preachers of note ("Pardoners") who carried them from town to town, collecting money and using their eloquence to recommend the good work in question and to enhance the spiritual privileges attached to it.