One of several neighbors of a person accused of a crime, or charged as a defendant in a civil action, who, appeared and swore that they believed him on his oath.
Law Dictionary – Alternative Legal Definition
Formerly, when a person was accused of a crime, or sued in a civil action, he might purge himself upon oath of the accusation made against him, whenever the proof was not the most clear and positive; and if upon his oath he declared himself innocent, he was absolved. 2. This usage, so eminently calculated to encourage perjury by impunity, was soon found to be dangerous to the public safety. To remove this evil the laws were changed, by requiring that the oath should be administered with the greatest solemnity; but the form was soon disregarded, for the mind became easily familiarized to those ceremonies which at first imposed on the imagination, and those who cared not to violate the truth did not hesitate to treat the form with contempt. In order to give a greater weight to the oath of the accused, the law was again altered so as to require that the accused should appear before the judge with a certain number of his neighbors, relations or friends, who should swear that they believed the accused had sworn truly. This new species of witnesses were called compurgators.