falseness

The state of being false; contrariety to the fact; inaccuracy; want of integrity or uprightness; double dealing; unfaithfulness; treachery; perfidy; as, the falseness of a report, a drawing, or a singer's notes; the falseness of a man, or of his word.

noun

1. An erroneous or false idea: erroneousness, error, fallacy, falsehood, falsity, untruth. See correct/incorrect, true/false.
2. Betrayal, especially of a moral obligation: disloyalty, faithlessness, false-heartedness, falsity, infidelity, perfidiousness, perfidy, traitorousness, treacherousness, treachery, unfaithfulness. See continue/stop/pause, trust/distrust.

The noun has 3 meanings:

Meaning #1: the state of being false or untrue
  Synonym: falsity

Meaning #2: unfaithfulness by virtue of being unreliable or treacherous
  Synonyms: faithlessness, fickleness, inconstancy

Meaning #3: the quality of not being open or truthful; deceitful or hypocritical
  Synonym: insincerity