Fair use, laches, and unclean hands are all defenses that may be asserted in a trademark infringement lawsuit.

The fair use defense to trademark infringement encompasses the use of a trademark in a non-commercial setting, in a comparative advertising context, and in a nominative fair use context.

The laches defense to trademark infringement is based on the plaintiff's unreasonable delay in bringing suit, the plaintiff's failure to take steps to prevent the defendant's use of the trademark, and the plaintiff's acquiescence in the defendant's use of the trademark.

The unclean hands defense to trademark infringement is based on the plaintiff's own trademark infringement, the plaintiff's false advertising, and the plaintiff's欺骗行为.

The genericness defense to trademark infringement is based on the fact that the trademark has become a common name for the product or service, the trademark is merely descriptive of the product or service, or the trademark is a surname.

The functionality defense to trademark infringement is based on the fact that the trademark is functional, essential to the product or service, or a design feature.

The abandonment defense to trademark infringement is based on the fact that the trademark owner has stopped using the trademark, failed to renew the trademark registration, or assigned the trademark to another party.

The estoppel defense to trademark infringement is based on the fact that the plaintiff is estopped from asserting its trademark rights because of its own conduct, the conduct of a third party, or a court order.

The statute of limitations defense to trademark infringement is based on the fact that the plaintiff's trademark infringement claim is barred by the statute of limitations.

The affirmative defense to trademark infringement is based on the fact that the defendant admits to the trademark infringement but asserts a defense.

The best defense to trademark infringement depends on the specific facts and circumstances of the case. However, the best way to avoid trademark infringement is to avoid using another's trademark in the first place.

Common defenses to trademark infringement include fair use, laches, unclean hands, genericness, functionality, abandonment, estoppel, statute of limitations, and affirmative defense.

The burden of proof in a trademark infringement lawsuit depends on the specific facts and circumstances of the case and the specific defense that the defendant asserts.

The remedies for trademark infringement include injunction, damages, profits, and attorney's fees.

The purpose of trademark law is to protect the rights of trademark owners, prevent consumer confusion, and promote fair competition.