The term 'Court Witness' Pledge' refers to the OATH taken by a witness in a court of law. This OATH is also known as an affirmation or a solemn promise to tell the truth. The four-letter solution for this crossword is 'OATH'. An OATH is a formal declaration that is made in the presence of a court or other authority, and it is usually sworn on a religious text or other sacred object. Taking an OATH is a serious matter, and it is important for witnesses to understand the consequences of not telling the truth.