Un‐truth″ (?), n. 1. The quality of being untrue; contrariety to truth; want of veracity; also, treachery; faithlessness; disloyalty. Chaucer.
2. That which is untrue; a false assertion; a falsehood; a lie; also, an act of treachery or disloyalty. Shak.
Syn. — Lie; falsehood. See Lie.