un·dorse /enˈdôrs/ Verb
1. Renege one's public approval or support of.
2. To not recommend (a product) in an advertisement.
Also: Undorsed, Undorsement.
In its latest publicity stunt, the racy teen retailer is offering to pay Mike "The Situation" Sorrentino — the "Jersey Shore" reality show cast member known for showing off his abdominal muscles, to not wear its merchandise. Abercrombie, effectively undorsed The Situation.
The act of telling people who NOT to vote for, buy from, or otherwise support.
As a staunch Republican, I will undorse Hillary Clinton in '08.