Unprepared for dreadful war (3)
I believe the answer is:
raw
'unprepared' is the definition.
(I've seen this in another clue)
'dreadful war' is the wordplay.
'dreadful' indicates anagramming the letters.
'war' is an anagram of 'RAW'.
'for' is the link.
(Other definitions for raw that I've seen before include "Uncooked; immature" , "Uncooked or sore" , "Like a recruit" , "Unrefined" , "Uncooked or unsophisticated" .)