Newspeak word, and one of the central pillars of Ingsoc. Crimestop refers to the ability to stop
short of any thought that might be heretical or unorthodox before it is even thought, as if by instinct. It is the ability to misunderstand analogies,
fail to perceive logical errors, and be repelled or bored by any train of thought or conversation that might be inimical to Ingsoc. Of course, this process is not unique to Ingsoc, and has been and still is applied by most religious and political extremists.
Crimestop is not stupidity, or at least not natural stupidity. It is the ability to deliberately
retard one's own
intelligence, and, of course, to forget the process of doing it by doublethink.