Warty hopper (4)
I believe the answer is:
toad
'warty hopper' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for toad that I've seen before include "Hall proprietor (Grahame)" , "Contemptible person" , "Tailless amphibian" , "species of amphibian" , "Wind in Willows hall-owner" .)