A military leader is not specific (7)
I believe the answer is:
general
This clue is a double definition.
'a military leader' is the first definition.
(general is a senior military rank)
'is not specific' is the second definition.
('general' is the opposite to 'specific')
(Other definitions for general that I've seen before include "Opposite of private!" , "Universal" , "Not specialised, rank" , "The senior officer is common and widespread" , "Rank; all-inclusive" .)