lip service

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

• noun Verbal expression of agreement or allegiance, unsupported by real conviction or action; hypocritical respect.

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

• noun idiomatic Empty talk; words absent of action or intention.
• noun slang, vulgar Cunnilingus, the act of using the mouth and tongue to stimulate the female genitals, especially the clitoris and labium. (Sometimes also referred to as giving lip.)

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

• noun an expression of agreement that is not supported by real conviction