A Deceit

1. An act or practice intended to deceive; a trick.
2. An act of deceiving someone.
3. (uncountable) The state of being deceitful or deceptive.
4. (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.

Synonyms

• (act or behavior intended to deceive): trick, fraud
• (act of deceiving): deception, trickery
• (state of being deceptive): underhandedness, deceptiveness, deceitfulness, dissimulation, fraudulence, trickery