Injured hothead carrying a weapon (6)
I believe the answer is:
harmed
'injured' is the definition.
(harming is a kind of injuring)
'hothead carrying a weapon' is the wordplay.
'hothead' becomes 'h' (head letter of 'hot').
'carrying a weapon' becomes 'armed' (I've seen this in another clue).
'h'+'armed'='HARMED'
(Other definitions for harmed that I've seen before include "Hurt" , "Injured or damaged" .)