Restore to life (6)
I believe the answer is:
'restore to life' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for revive that I've seen before include "Wake up" , "(Cause to) get new life" , "Bring back to consciousness or from obscurity" , "Bring back to consciousness or life" , "Restore to life or consciousness" .)