Disorganised secret agent receiving discharge (7)
I believe the answer is:
scrappy
'disorganised' is the definition.
(I've seen this before)
'secret agent receiving discharge' is the wordplay.
'secret agent' becomes 'spy' (spy is a kind of secret agent).
'receiving' is an insertion indicator.
'discharge' becomes 'crap' (term for excrement, a type of discharge).
'spy' placed around 'crap' is 'SCRAPPY'.
(Other definitions for scrappy that I've seen before include "Fragmented" , "Disjointed" , "Fragmentary" , "disorganised" .)