Trademark tarnishment is a form of trademark infringement. A person accused of trademark tarnishment may be able to defend herself against the claim in certain circumstances. A trademark is a symbol, word, short phrase or sentence, or a combination of these that the public associates with a particular business or product. Trademarks registered with the U.S. Trademark and Patent Office are protected by law against unauthorized use by parties other than the registrant. For example, if another company uses the words "Tootsie Roll" on a candy for sale to the public, that company could be said to have tarnished the trademarked name "Tootsie Roll," the candy made famous by Tootsie Roll Industries.
If a trademark infringer uses a well-known name or mark that the public associates with a specific item, that use is said to dilute the trademark. Blurring is an act that may cause the public to associate the trademark with a use that is different from the use that is covered by the trademark. Tarnishment occurs when the dilution or blurring of another party's trademark damages that party's reputation. For example, if an adult pornography store uses a name or phrase that is the same as, or close to, the trademark registered by a toy company, the toy company may allege that this use harms its reputation as a child's toy company.
A person accused of trademark tarnishment may claim "fair use" as a defense. Fair use means the person used the trademark in a way that reflects its actual meaning and doesn't cause customer confusion. For example, if a cereal company describes a product ingredient as containing "oat bran" on the back of a cereal box, and "oat bran" is part of the trademarked name of another cereal, the mention of the words in the ingredient list is considered a fair use. The primary meaning of the trademarked words is used appropriately, and customers are unlikely to confuse the product description with the trademarked brand of cereal.
Nominative use is another trademark tarnishment defense that is related to fair use, according to the Berkman Center for Internet & Society at Harvard University. Nominative use occurs when the person accused of tarnishment had no choice but to use that particular trademarked word or phrase to identify another party and wasn't identifying a product of her own or endorsing or sponsoring the trademark holder. For example, a business that repairs cars of a trademarked company, such as General Motors, may claim nominative use when using the trademarked name in its advertisements. What the business can't do is falsely claim in the ads that it has an established relationship with the manufacturer. For example, a car repair company can't advertise that it is an "authorized" repair company for a specific car manufacturer when it has no authorization from the manufacturer.
Parodies involving the use of a trademark may be protected against tarnishment claims made by the trademark holder. As an artistic act, a parody sometimes qualifies for protection under the First Amendment to the U. S. Constitution, which prevents laws from infringing on the right to free speech. State and federal courts differ on how to balance a person's First Amendment rights with the laws protecting trademarks, according to the Berkman Center for Internet & Society at Harvard University. In most cases of parody, a successful defense to a claim of tarnishment should not directly relate to the trademark's commercial use. For example, an artist using a trademark in an online parody skit may be protected under the First Amendment, but a rival company parodying that same trademark in a commercial for a similar product without permission from the trademark holder might not be able to claim parody as a defense to a tarnishment claim.