A person who ransoms someone or something, a person who pays a ransom; a redeemer, specifically (now frequently with capital initial) Christ.
A person held as security for the payment of a ransom for a ship.
A member of the Order of Our Lady of Ransom (also called Our Lady of Mercy), founded in the 13th century to free Christians taken prisoner by the Muslims; = Mercedarian.
A member of the Guild of Our Lady of Ransom, founded in 1887 with the principal aim of converting England and Wales to the Roman Catholic faith.