Men do turn to the devil (5)
I believe the answer is:
demon
'the devil' is the definition.
('demon' can be a synonym of 'devil')
'men do turn' is the wordplay.
'turn' indicates anagramming the letters.
'men'+'do'='mendo'
'mendo' is an anagram of 'DEMON'.
'to' acts as a link.
(Other definitions for demon that I've seen before include "Fiend, devil" , "Devil - master performer" , "ace" , "Wizard" , "Ghoul" .)