Falsehood

Any untrue assertion or proposition; a willful act or declaration contrary to the truth. It does not always and necessarily imply a lie or willful untruth, but is generally used in the second sense here given. It is committed either by the willful act of the party, or by dissimulation, or by words. It is willful, for example, when the owner of a thing sells it twice, by different contracts, to different individuals, unknown to them; for in this the seller must willfully declare the thing is his own when he knows that it is not so. It is committed by dissimulation when a creditor, having an understanding with his former debtor, sells the land of the latter although he has been paid the debt which was due to him. Falsehood by word is committed when a witness swears to what he knows not to be true.

See Rose. Crim. Ev. 362.