Old communist figure turning back on Left (5)
I believe the answer is:
lenin
'old communist' is the definition.
'figure turning back on left' is the wordplay.
'figure' becomes 'nine' (I've seen this in other clues**).
'turning back' is a reversal indicator.
'on' is a charade indicator (letters next to each other).
'left' becomes 'l' (common abbreviation).
'nine' in reverse letter order is 'enin'.
'enin' put after 'l' is 'LENIN'.
(Other definitions for lenin that I've seen before include "Leader of the Russian Revolution" , "Revolutionary leader" , "Marxist theoretician" , "First Soviet leader" , "First premier of the Soviet Union, d. 1924" .)