A Moslem leader always a Moslem leader (5)
I believe the answer is:
ameer
'a moslem leader' is the definition.
(I've seen this in another clue)
'a moslem leader always' is the wordplay.
'leader' suggests taking the first letters.
'always' becomes 'eer' (poetic way of saying ever).
The first letter of 'moslem' is 'm'.
'a'+'m'+'eer'='AMEER'
(Other definitions for ameer that I've seen before include "Eastern potentate (variant spelling)" , "Muslim leader" , "Asian dignitary" , "Former ruler's title in Afghanistan" , "foreign ruler" .)