Dream about being prepared for war (5)
I believe the answer is:
armed
'prepared for war' is the definition.
(I've seen this in another clue)
'dream about' is the wordplay.
'about' is an anagram indicator.
'dream' with letters rearranged gives 'ARMED'.
'being' is the link.
(Other definitions for armed that I've seen before include "Equipped with weapons" , "Provided with weapons" , "prepared to shoot?" , "Supplied with weapons" , "Munitioned" .)