› LAW a statement made by someone in a court of law in which they say if they are guilty of something that they are accused of: a guilty/not guilty plea The guilty plea will mark the second time in eight years that the oil company has been convicted of a federal environmental crime in Alaska.a plea of guilty/not guilty She entered a plea of not guilty in federal court Friday to multiple extortion and bribery charges.enter/withdraw a plea Recent reforms will allow them to enter a plea of diminished political responsibility.