deceit

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The act or practice of deceiving; deception.
2. n. A stratagem; a trick.
3. n. The quality of being deceitful; falseness.

Century Dictionary and Cyclopedia

1. n. The quality of being false or misleading; falseness; falsehood; deception; deceptiveness.
2. n. The act or practice of deceiving; concealment or perversion of the truth for the purpose of misleading; fraud; cheating.
3. n. That which deceives; action or speech designed to mislead or beguile; a guileful artifice.
4. n. In law, any trick, device, craft, collusion, false representation, or underhand practice, used to defraud another: now more commonly called fraud or misrepresentation. Synonyms and Deceit, Deception, Fraud, craft, cunning, duplicity, double-dealing, guile, trickery, wiliness, treachery, finesse, imposture. Deceit is a shorter and more energetic word for deceitfulness, indicating the quality; it is also, but more rarely, used to express the act or manner of deceiving. The reverse is true of deception, which is properly the act or course by which one deceives, and not properly the quality; it “may express the state of being deceived. Fraud is an act or a series of acts of deceit by which one attempts to benefit himself at the expense of others. It is generally a breaking of law; the others are not. See artifice and deceptive.

Wiktionary

1. n. An act or practice intended to deceive; a trick
2. n. An act of deceiving someone
3. n. The state of being deceitful or deceptive
4. n. The tort or fraudulent representation of a material fact made with knowledge of its falsity, or recklessly, or without reasonable grounds for believing its truth and with intent to induce reliance on it; the plaintiff justifiably relies on the deception, to his injury.

GNU Webster's 1913

1. n. An attempt or disposition to deceive or lead into error; any declaration, artifice, or practice, which misleads another, or causes him to believe what is false; a contrivance to entrap; deception; a wily device; fraud.
2. n. Any trick, collusion, contrivance, false representation, or underhand practice, used to defraud another. When injury is thereby effected, an action of deceit, as it called, lies for compensation.

WordNet 3.0

1. n. a misleading falsehood
2. n. the act of deceiving
3. n. the quality of being fraudulent