The general was defeated in the decisive conflict.

defeated 是动词 defeat 的过去分词形式，在句中表示被动。defeat 的意思是"击败、战胜"，由前缀 de-（表示"去除、剥夺"）和词根 feat（来自拉丁语 factum，意为"完成、成就"）组成，字面意思是"使对方的成就失效"。defeated 表示"被击败的"。