Is there a word for being so polite as to appear insincere?

I'm looking for a term in English to describe being so polite that one appears to be insincere.

This is a good page which may be helpful to you. My picks would be the following:

• smarmy: using societal constraints/rules (i.e. politeness) to passive-aggresively/non-confrontationally get one's way. That's my interpretation, but here's an article about it.
• oily/greasy: like a businessman or shopkeeper or something who dotes on clients/customers so heavily (and maybe crosses personal-space boundaries in so doing) that it's almost viscerally unpleasant.
• obsequious: I would say that obsequious is more subtle than the others, but again, that's my interpretation. Look for uses in books or something.

I disagree with the MacMillan page on the following points:

• 'Suave' I take to mean smooth, well-dressed, and having nice things, with no connotation of insincerity.
• 'Proper' I take to mean stiff or rigid politeness; again, not necessarily insincere (cranky people besotted with their rules can be sincere!)

I like unctuous...

unc·tu·ous [uhngk-choo-uhs] adjective 1. characterized by excessive piousness or moralistic fervor, especially in an affected manner; excessively smooth, suave, or smug.

http://dictionary.reference.com/browse/unctuous?s=ts

saccharine, adj.

1. Of, relating to, or characteristic of sugar or saccharin; sweet.

2. Having a cloyingly sweet attitude, tone, or character: a saccharine smile.

Literally, it is a chemical that is an artificial sweetener. Figuratively, it can be used to describe a person or action that is so sweet it seems to be artificial.