A man to turn to (4)
I believe the answer is:
otto
'a man' is the definition.
(I have seen 'A man' mean 'otto' so perhaps 'man' could also mean 'otto')
'to turn to' is the wordplay.
'turn' is a reversal indicator.
'to' in reverse letter order is 'ot'.
'ot'+'to'='OTTO'
(Other definitions for otto that I've seen before include "Preminger or von Bismark?" , "- - Preminger (films)" , "Palindromic man's name" , "Palindromic German name like Bismark's" , "German king" .)