A more thorough explanation:

The sweat-of-the-brow doctrine used to be a principle that said copyrights could protect the hard work and money that went into creating a work, rather than just the originality of the work itself. For example, if someone spent a lot of time and effort compiling a phone book, they could claim copyright protection for it, even though the information in the phone book was not original.

However, in 1991, the Supreme Court rejected this doctrine in a case called Feist Pubs., Inc. v. Rural Tel. Servs. Co. The court said that copyright protection should only be given to works that are original and creative, not just those that required a lot of effort to create.

For example, if someone takes a photograph of a famous landmark, they cannot claim copyright protection just because they spent a lot of time and money traveling to the location and setting up the shot. The photograph must be original and creative in order to be protected by copyright law.