Mean mien (5)
I believe the answer is:
sneer
'mean mien' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sneer that I've seen before include "A scornful expression or remark" , "Contemptuous or mocking smile" , "Dig" , "Contemptuous look" , "Derisive remark" .)