Satan was revolting (5)
I believe the answer is:
devil
'satan' is the definition.
(I know that satan can be written as Devil)
'was revolting' is the wordplay.
'was' becomes 'lived' (to live is to be).
'revolting' says the letters should be written backwards.
'lived' back-to-front is 'DEVIL'.
(Other definitions for devil that I've seen before include "Terror" , "See 11" , "Old Nick, Satan" , "Wicked person" , "Unsurpassed" .)