Believability. The major legal application of the term credibility relates to the testimony of a witness or party during a trial. Testimony must be both competent and credible if it is to be accepted by the trier of fact as proof of an issue being litigated.
The credibility of a witness or party is based upon the ability of the jury to trust and believe what he or she says, and relates to the accuracy of his or her testimony as well as to its logic, truthfulness, and sincerity. Personal credibility depends upon the qualities of a person that would lead a jury to believe or disbelieve what the person said.