Imagine being armed badly (5)
I believe the answer is:
dream
'imagine' is the definition.
(dreaming is a kind of imagining)
'armed badly' is the wordplay.
'badly' indicates anagramming the letters (letters in the wrong order).
'armed' is an anagram of 'DREAM'.
'being' is the link.
(Other definitions for dream that I've seen before include "Vision, fantasy" , "person to good to be true" , "Part of sleep" , "Armed (anag)" , "Sleeper's vision" .)