Imitate a lion (4)
I believe the answer is:
roar
'imitate a lion' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for roar that I've seen before include "Noise of lion" , "24 [BOOM]" , "Loud noise of angry bull" , "Bellow, holler" , "Loud growl" .)