Retired pilot's explosive deed (7)
I believe the answer is:
exploit
'deed' is the definition.
(synonyms)
'retired pilot's explosive' is the wordplay.
'retired' becomes 'ex' (prefix meaning former or onetime).
'explosive' is an anagram indicator.
'pilot' anagrammed gives 'ploit'.
'ex'+'ploit'='EXPLOIT'
(Other definitions for exploit that I've seen before include "Benefit from" , "Take advantage of - feat" , "Heroic achievement" , "The deed to make gain from" , "Bunk" .)