Servant's farewell to Turkish leader (5)
I believe the answer is:
valet
'servant's' is the definition.
(valet is a kind of servant)
'farewell to turkish leader' is the wordplay.
'farewell' becomes 'vale' (I've seen this before).
'leader' suggests taking the first letters.
The first letter of 'turkish' is 't'.
'vale'+'t'='VALET'
(Other definitions for valet that I've seen before include "Gentleman's gentleman" , "Personal male assistant" , "Man's personal attendant" , "Jeeves?" , "Gentleman's attendant" .)