snide

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Mocking or derogatory in a malicious or ironic way.
• adjective Making or given to making snide remarks.

from The Century Dictionary.

• Sharp; characterized by low cunning and sharp practice; tricky; also, false; spurious.
• noun An underhanded, tricky person given to sharp practice; a sharper: a beat.
• noun A spurious object; a humbug; a fake; something designed to cheat.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Slang, archaic Tricky; deceptive; contemptible
• adjective derogatory in an insinuating manner.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Sharp.
• adjective Characterised by low cunning and sharp practise.
• adjective Disparaging or derisive in an insinuative way.
• adjective Tricky; deceptive; false; spurious; contemptible.
• noun An underhanded, tricky person given to sharp practise; a sharper; a beat.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective expressive of contempt