Sneering, scornful (5)
I believe the answer is:
snide
I believe this is a double definition.
'sneering' is the first definition.
(I know that sneering can be written as snide)
'scornful' is the second definition.
(I've seen this in another clue)
(Other definitions for snide that I've seen before include "Derogatory, mocking" , "Dines (anag.)" , "Mean, base" , "such remarks aren't nice" , "Supercilious, malicious" .)