The right of the copyright owner to have the opportunity to receive payment for every copy!
Caution: The creator of an original work may not own the copyright. If you produce a “work for hire”, the employer may claim the copyright.
Plagiarism is theft of credit. Bad, but not illegal. However, teachers may equate plagiarism with cheating. Socially, this can ruin a political or writing career.
Copyright infringement implies theft of profit opportunity.