Follow wagger (4)
I believe the answer is:
tail
I believe this is a double definition.
'follow' is the first definition.
(both can mean to chase or pursue)
'wagger' is the second definition.
(something that wags)
(Other definitions for tail that I've seen before include "Shadow" , "that can be cast by a lizard" , "Follow closely - taper (off)" , "Hindmost part" , "Rear appendage of animal" .)