WordNet (r) 3.0 (2006):
doublethink n 1: believing two contradictory ideas at the same timeMoby Thesaurus II by Grady Ward, 1.0:
22 Moby Thesaurus words for "doublethink": Janus, ambiguity, ambivalence, biformity, bifurcation, conjugation, dichotomy, doubleness, doubling, dualism, duality, duplexity, duplication, duplicity, equivocality, halving, irony, pairing, polarity, twinning, two-facedness, twoness