Terrible barney not far away (6)
I believe the answer is:
nearby
'not far away' is the definition.
(I've seen this before)
'terrible barney' is the wordplay.
'terrible' indicates anagramming the letters.
'barney' with letters rearranged gives 'NEARBY'.
(Other definitions for nearby that I've seen before include "Just round the corner?" , "Adjacent" , "somewhere close" , "Around the corner" , "Local" .)