A newspeak word created by George Orwell for his book Nineteen Eigty-Four.

The definition according to Orwell: "this word has two mutually contradictory meanings. Applied to an opponent, it means the habit of impudently claiming that black is white, in contradiction of the plain facts. Applied to a Party member, it means a loyal willingness to say that black is white when Party discipline demands this. But it means also the ability to believe that black is white, and more, to know that black is white, and to forget that one has ever believed the contrary. This demands a continuous alteration of the past, made possible by the system of thought which really embraces all the rest, and which is known in Newspeak as doublethink. " —Orwell, 1984

The word is an example of doublethink, which is the ability to rewrite the past as the party commands it. An example of the parties ability to control the thoughts and minds of the party members. True party members are able to automatically reject what the party says is false, and accept what the party says is true.