New role for knowledge (4)
I believe the answer is:
lore
'for knowledge' is the definition.
(lore is a kind of knowledge)
'new role' is the wordplay.
'new' indicates an anagram.
'role' is an anagram of 'LORE'.
(Other definitions for lore that I've seen before include "Role for tradition" , "Old learning" , "Ancient learning" , "Role for body of traditions" , "old-fashioned thong" .)