His angst explodes in battle (8)
I believe the answer is:
hastings
'battle' is the definition.
(I know that Hastings is a pitched battle)
'his angst explodes' is the wordplay.
'explodes' indicates anagramming the letters.
'his'+'angst'='hisangst'
'hisangst' is an anagram of 'HASTINGS'.
'in' acts as a link.
(Other definitions for hastings that I've seen before include "His angst (anag.)" , "somewhere in Sussex" , "place of battle" , "South coast resort" , "Ten sixty six battle" .)