Grenade exploded by English traitor (8)
I believe the answer is:
renegade
'traitor' is the definition.
(I've seen this before)
'grenade exploded by english' is the wordplay.
'exploded' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'english' becomes 'e' (abbreviation).
'grenade' is an anagram of 'renegad'.
'renegad'+'e'='RENEGADE'
(Other definitions for renegade that I've seen before include "Treacherous person" , "Treacherous deserter" , "Dare Gene to become a rebel" , "Deserter, turncoat" , "Turncoat, rebel" .)