A thought-terminating cliché is a commonly used phrase, sometimes passing as folk wisdom, used to propagate cognitive dissonance (discomfort experienced when one simultaneously holds two or more conflicting cognitions, e.g. ideas, beliefs, values or emotional reactions). Though the phrase in and of itself may be valid in certain contexts, its application as a means of dismissing dissent or justifying fallacious logic is what makes it thought-terminating.
The term was popularized by Robert Jay Lifton in his 1956 book Thought Reform and the Psychology of Totalism. Lifton said, “The language of the totalist environment is characterized by the thought-terminating cliché. The most far-reaching and complex of human problems are compressed into brief, highly reductive, definitive-sounding phrases, easily memorized and easily expressed. These become the start and finish of any ideological analysis.” 
In George Orwell’s novel Nineteen Eighty-Four, the fictional constructed language Newspeak is designed to reduce language entirely to a set of thought-terminating clichés. Aldous Huxley’s Brave New World society uses thought-terminating clichés in a more conventional manner, most notably in regard to the drug soma as well as modified versions of real-life platitudes, such as, “A doctor a day keeps the jim-jams away.”
Thought-terminating clichés are sometimes used during political discourse to enhance appeal or to shut down debate. In this setting, their usage can usually be classified as a logical fallacy.]]
Thought-terminating clichés are also present in religious discourse in order to define a clear border between good and evil, holiness and sacrilege, and other polar opposites. These are especially present in religious literature.
- “The Lord giveth, and the Lord taketh away.” Job 1:21
- “Adam and Eve, not Adam and Steve!” (opposing same-sex marriage)
- “That’s not Biblical.”
- “God moves/works in mysterious ways.”
- “God never gives you more suffering than you can bear.”
- “Only God can judge.”
- “God has a plan.”
- “The Lord works in mysterious ways.”
The religious or semi-religious ideas of cults, heretics, and infidels are also often used as thought-terminating clichés, e.g. “Do not listen to him, he is an infidel,” (a guilt by association fallacy) or “That line of thought sounds like a cult” (also a guilt by association fallacy).
As an autological phrase
The statement “that is a thought-terminating cliché” can itself function as a thought-terminating cliché. Once the stator has identified a first statement as a thought-terminating cliché, they may feel absolved of needing to determine whether that first statement is indeed a thought-terminating cliché, or provides useful insight, in the context under discussion.
- Loaded language
- Godwin’s law
- Fighting words
- Language in Thought and Action by S. I. Hayakawa