Dragon made terrible battle (10)
I believe the answer is:
armageddon
'battle' is the definition.
(I know that Armageddon is a type of battle)
'dragon made terrible' is the wordplay.
'terrible' indicates anagramming the letters.
'dragon'+'made'='dragonmade'
'dragonmade' is an anagram of 'ARMAGEDDON'.
(Other definitions for armageddon that I've seen before include "Terrible war" , "battle in Revelation" , "large-scale conflict" , "ultimate conflict" , "bloody battle" .)