Facing the accusation, she immediately retorted that the other party was the real source of the problem.

retorted 是动词 retort 的过去式。retort 由前缀 re-（表示"回、反"）和词根 tort（来自拉丁语 torquere，意为"扭转"）组成，字面意思是"扭转回去"，引申为"反驳、回嘴"的意思。在句中表示她立即用言语反击对方的指责。