A powerful plea is a moving and persuasive appeal, often used in legal contexts, to obtain a favorable outcome. Synonyms for a powerful plea include a compelling argument, a convincing request, an impassioned petition, a heartfelt entreaty, a sincere supplication, and a strong and convincing case. Other words that can be used to describe a powerful plea are a forceful appeal, a heartfelt appeal, a fervent appeal, a persuasive appeal, and an urgent appeal. The key to a powerful plea is to convey a sense of urgency and sincerity, and to present a strong case that is backed by evidence and emotion.