The mental ability to understand the general effect of a transaction or document.
The legal fitness or ability of a witness to be heard on the trial of a cause. This term is also applied to written or other evidence which may be legally given on such trial as depositions, letters, account-books and the like.
Prima facie every person offered is a competent witness and must be received, unless his incompetency appears.
There is a difference between competency and credibility. A witness may be competent and on examination his story may be so contradictory and improbable that he may not be believed; on the contrary he may be incompetent and yet be perfectly credible if he were examined.
The court are the sole judges of the competency of a witness, and may, for the purpose of deciding whether the witness is or is not competent, ascertain all the facts necessary to form a judgment.
In the French law, by competency is understood the right in a court to exercise jurisdiction in a particular case; as where the law gives jurisdiction to the court when a thousand francs shall be in dispute, the court is competent if the sum demanded is a thousand francs or upwards although the plaintiff may ultimately recover less.