Comply with old Turkish governor (4)
I believe the answer is:
obey
'comply with' is the definition.
(I've seen this in another clue)
'old turkish governor' is the wordplay.
'old' becomes 'o' (abbreviation).
'turkish governor' becomes 'bey' (term for a governor in the Ottoman Empire).
'o'+'bey'='OBEY'
(Other definitions for obey that I've seen before include "Toe the line" , "Carry out (a command)" , "Follow orders" , "Conform" , "Do as ordered" .)