Libel does not cause any tangible harm to a person. I assure you that has been illegal for some time.
Libel is written, slander is spoken.
But, since that's besides the point, if Bob says Jim's restaraunt uses horse meat when it doesn't, and Jim's business goes down because of this rumor, there is tangible harm(maybe I should have been more specific, it's not just physical harm that applies, since speech can't hurt you at all). Further though, this is once again besides the point - a curse word isn't slander by any means, and as far as I know can't really cause any harm to another person.