The attempt to pass the new law was narrowly defeated in the Senate.

defeated 是动词 defeat 的过去分词形式，在句中表示被动。defeat 由前缀 de-（表示"向下、去除"）和词根 feat（来自拉丁语 facere，意为"做"）组成，字面意思是"使...做不成"，引申为"击败、否决"的意思。defeated 在这里表示"被否决"的状态。