Many needing saviour's conversion (7)
I believe the answer is:
various
'many' is the definition.
(thesaurus)
'saviour's conversion' is the wordplay.
'conversion' indicates anagramming the letters.
'saviour' with letters rearranged gives 'VARIOUS'.
'needing' is the link.
(Other definitions for various that I've seen before include "Divers" , "Saviour of different types" , "Disparate, diverse" , "Saviour of many kinds" , "Sundry" .)