Opponents seem in disarray after the end of the battle (7)
I believe the answer is:
enemies
'opponents' is the definition.
(I know this)
'seem in disarray after the end of the battle' is the wordplay.
'disarray' indicates anagramming the letters.
'after' means one lot of letters go next to another.
'the end of' suggests the final letters.
The final letter of 'battle' is 'e'.
'seem'+'in'='seemin'
'seemin' is an anagram of 'nemies'.
'nemies' after 'e' is 'ENEMIES'.
(Other definitions for enemies that I've seen before include "Foes, opponents" , "Foes, adversaries" , "Those we fight" , "Foes, hostile groups" .)