Menacing look (5)
I believe the answer is:
scowl
'menacing look' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for scowl that I've seen before include "Glare" , "Bad-tempered expression" , "Angrily frown" , "Gloomy or threatening expression" , "Lower" .)