Show one’s teeth (5)
I believe the answer is:
snarl
'show one's teeth' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for snarl that I've seen before include "Tangle; growl" , "(Make an) aggressive noise" , "Show one's teeth (like a lion)" , "Growl viciously" , "Growl with bared teeth" .)