Rehashing means to present something old in a new or slightly different form. It's often used in a negative context, implying that the new presentation lacks originality or substance.
Here are some examples of rehashing:
* A movie that rehashes an old plot with new characters.
* A writer rehashing old ideas in a new book.
* A politician rehashing old campaign promises.
The implication is that the material has been presented before and isn't truly fresh or innovative. It's essentially recycling old content.