Saviour (7)
(Other definitions for messiah that I've seen before include "Jesus?" , "Handel's composition sung at Christmas" , "Hallelujah chorus work" , "Choral work often performed at Christmas" , "Expected deliverer of the Jews" .)
(Other definitions for rescuer that I've seen before include "One who saves someone" , "One who saves another from peril" , "freer" , "One who saves from a dangerous situation" , "one retrieves" .)
(Other definitions for white knight that I've seen before include "Someone coming to the rescue" , "Heroic champion (of the chessboard?)" .)
'saviour' is the definition.
(I know this)
This is the entire clue.
(Other definitions for redeemer that I've seen before include "One saving another from sin" , "One who delivers (people) from sin" , "One who saves (sinner)" , "One who saves (another) from sin" , "Mere deer for the saviour" .)