In the World of George Orwell’s Nineteen Eighty-Four, Airstrip One is brutally lorded over by the one-party government of Big Brother and INGSOC. All forms of dissent, even down to peoples’ facial expressions or questioning thoughts were a crime.
In the novel, crimestop is a term used that means to rid oneself of unwanted thoughts, i.e., thoughts that interfere with the ideology of the INGSOC Party. This way, a person avoids committing thoughtcrime.
In the novel, we hear about crimestop through the eyes of protagonist Winston Smith:
“The mind should develop a blind spot whenever a dangerous thought presented itself. The process should be automatic, instinctive. Crimestop, they called it in Newspeak. He set to work to exercise himself in crimestop. He presented himself with propositions — ‘the Party says the earth is flat’, ‘the party says that ice is heavier than water’ — and trained himself in not seeing or not understanding the arguments that contradicted them.”