What offense is committed when a man sells counterfeit t-shirts online?

The offense committed when a man sells counterfeit t-shirts online is trademark counterfeiting. This action involves the unauthorized use of a registered trademark on goods that are not genuine. In this case, the t-shirts are falsely branded with a trademark that they do not represent, thereby misleading consumers into believing they are purchasing authentic items. Trademark counterfeiting undermines the brand's reputation, can harm consumers, and violates intellectual property laws designed to protect both the trademark owners and the public from deception.

Fraud, while a relevant concept, typically involves deceit for personal gain that does not necessarily pertain to trademarked items. Intellectual property theft is a broader term that encompasses various forms of infringement but specifically selling counterfeit items falls more precisely under trademark counterfeiting. False advertising would pertain to misleading claims about a product rather than the use of a counterfeit trademark, making trademark counterfeiting the most accurate classification for this offense.