Wildebeest (3)
I believe the answer is:
gnu
'wildebeest' is the definition.
(I know that wildebeest can be written as gnu)
This is the entire clue.
(Other definitions for gnu that I've seen before include "Animal" , "Wildebeest" , "animals" , "Large heavy antelope" , "Antelope sounds as if it has knowledge" .)