plea bargain noun 1plea-bargain verb 1forms 4 noun1 •(US) An agreement in which a defendant agrees to plead guilty to a lesser charge instead of not guilty to a greater one plea-bargain verb1 •(US) To make an agreement in which a defendant agrees to plead guilty to a lesser charge instead of not guilty to a greater one. formsplea-bargained · plea-bargaining · plea-bargains · plea bargains