Crikey, wild hogs! (4)
I believe the answer is:
gosh
'crikey' is the definition.
(I've seen this before)
'wild hogs' is the wordplay.
'wild' indicates an anagram.
'hogs' anagrammed gives 'GOSH'.
(Other definitions for gosh that I've seen before include "English infirmary" , "I'm amazed!" , "Crikey" , "Good heavens!" , "Christmas" .)