re·pu·di·ate

[ri-pyoo-dee-eyt]

verb

1. to reject as having no authority or binding force: to repudiate a claim.
2. to cast off or disown: to repudiate a son.
3. to reject with disapproval or condemnation: to repudiate a new doctrine.
4. to reject with denial: to repudiate a charge as untrue.
5. to refuse to acknowledge and pay (a debt), as a state, municipality, etc.

Source: http://dictionary.reference.com/browse/repudiate