Lawn pest (4)
I believe the answer is:
mole
'lawn pest' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for mole that I've seen before include "Tunneller" , "sauce" , "Burrowing mammal with velvety fur" , "Dark spot on skin or burrowing animal" , "Adrian ---, fancies Pandora; lurking spy" .)