Dog – badger (5)
I believe the answer is:
hound
I believe this is a double definition.
'dog' is the first definition.
(hound is a type of dog)
'badger' is the second definition.
(I've seen this before)
(Other definitions for hound that I've seen before include "Pursue relentlessly" , "Harry" , "Give no peace" , "Follow" , "Chase after" .)