cower in fear (5)
I believe the answer is:
quail
'cower in fear' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for quail that I've seen before include "Show fear - of small game bird?" , "Cower before the game-bird?" , "Shrink; a bird" , "Game bird - cower" , "See little bird" .)