deceit

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or practice of deceiving; deception.
• noun A stratagem; a trick.
• noun The quality of being deceitful; falseness.

from The Century Dictionary.

• noun The quality of being false or misleading; falseness; falsehood; deception; deceptiveness.
• noun The act or practice of deceiving; concealment or perversion of the truth for the purpose of misleading; fraud; cheating.
• noun That which deceives; action or speech designed to mislead or beguile; a guileful artifice.
• noun In law, any trick, device, craft, collusion, false representation, or underhand practice, used to defraud another: now more commonly called fraud or misrepresentation.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.
• noun (Law) 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An act or practice intended to deceive; a trick
• noun An act of deceiving someone
• noun uncountable The state of being deceitful or deceptive
• noun law 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.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a misleading falsehood
• noun the act of deceiving
• noun the quality of being fraudulent