A frameup refers to the act of "framing" someone, that is, providing false evidence in order to prove someone guilty of a crime. Sometimes the person who is framing someone else is the actual perpetrator of the crime. In some other cases it is an attempt by law enforcement to neutralize a criminal who has escaped conviction, or to remove a political dissident. Some criminals will attempt to falsely claim they were framed as a defense strategy.
The term comes from the criminal subculture, with an early version being the claim that "someone is trying to put me in the frame," as in a picture frame.
Although frameups usually occur by creating false evidence, sometimes people will employ identity theft instead as it is often cheaper to take advantage of lax computer security than go through the trouble of impersonating someone else physically, because many usual behaviors must be recorded and practiced in order to create realistic evidence.