Dream about having weapons (5)
I believe the answer is:
armed
'having weapons' is the definition.
(I've seen this in another clue)
'dream about' is the wordplay.
'about' indicates an anagram.
'dream' is an anagram of 'ARMED'.
(Other definitions for armed that I've seen before include "Tooled up" , "prepared to shoot?" , "ready to fight" , "Equipped with weapons" , "Being equipped with 25 Across" .)