Newspeak word, and one of the pillars of Ingsoc. Like many Newspeak words, it has two contradictory meanings. In a positive sense, it means someone who is able to believe that black is white, or that two plus two makes five, if the Party wishes it. In the negative sense, it means someone who believes that black is white when it is obviously not (i.e. only if the Party does not wish it to be).
"How many fingers am I holding up, Winston?"
"Four! Four! What else can I say? Four!"