falsehood

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An untrue statement; a lie.
2. n. The practice of lying.
3. n. Lack of conformity to truth or fact; inaccuracy.

Century Dictionary and Cyclopedia

1. n. The fact or quality of being false; falseness; dishonest purpose or intention; treachery; deceitfulness; perfidy: opposed to truthfulness.
2. n. That which is false; a false representation in word or deed; an untruth; a lie: as, the tale is a series of falsehoods; to act a falsehood.
3. n. False manifestation or procedure; deceitful speech, action, or appearance; counterfeit; imposture; specifically, in law, a fraudulent imitation or suppression of truth to the prejudice of another.
4. n. Synonyms Falsehood, Falseness, Falsity; untruth, fabrication, fiction. Instances may be quoted in abundance from old authors to show that the first three words are often strictly synonymous; but the modern tendency has been decidedly in favor of separating them, falsehood standing for the concrete thing, an intentional lie; falseness, for the quality of being guiltily false or treacherous: as, he is justly despised for his falseness to his oath; and falsity, for the quality of being false without blame: as, the falsity of reasoning.

Wiktionary

1. n. uncountable The property of being false.
2. n. countable A false statement, especially an intentional one; a lie
3. n. archaic, rare Mendacity, deceitfulness; the trait of a person who is mendacious and deceitful.

GNU Webster's 1913

1. n. Want of truth or accuracy; an untrue assertion or representation; error; misrepresentation; falsity.
2. n. A deliberate intentional assertion of what is known to be untrue; a departure from moral integrity; a lie.
3. n. Treachery; deceit; perfidy; unfaithfulness.
4. n. A counterfeit; a false appearance; an imposture.

WordNet 3.0

1. n. the act of rendering something false as by fraudulent changes (of documents or measures etc.) or counterfeiting
2. n. a false statement