Wartime colonel no leader, ineffective (4)
I believe the answer is:
limp
'ineffective' is the definition.
(thesaurus)
'wartime colonel no leader' is the wordplay.
'wartime colonel' becomes 'blimp' (cartoon character Colonel Blimp).
'no leader' means to remove the first letter.
'blimp' with its first letter taken away is 'LIMP'.
(Other definitions for limp that I've seen before include "Walk unevenly; not stiff" , "Walk badly; not stiff" , "obstacle to smooth progress" , "Weak" , "Not stiff or firm" .)