Are turning right back (4)
I believe the answer is:
rear
'back' is the definition.
(something's rear is its back)
'are turning right' is the wordplay.
'turning' is an anagram indicator.
'right' becomes 'r' (common abbreviation).
'are' with letters rearranged gives 'rea'.
'rea'+'r'='REAR'
(Other definitions for rear that I've seen before include "The back part of something" , "Hitchcock film set in one room" , "Rump" , "Buck" , "Hindmost part" .)