“彻底打败”常见的英文表达有 completely defeat、utterly defeat、thoroughly crush 或 soundly defeat 等，具体可根据语境选择：
completely defeat：强调“完全地、彻底地击败”，侧重于结果上的全面胜利。
例句：The army was able to completely defeat the enemy.（这支军队能够彻底打败敌人。）
utterly defeat：“utterly”表示“完全地、绝对地”，语气更强烈，强调彻底的程度。
例句：Their efforts to resist were utterly defeated.（他们抵抗的努力被彻底打败了。）
thoroughly crush：“thoroughly”表示“彻底地、完全地”，“crush”有“压碎、击垮”之意，该短语形象地表达出将对方彻底击垮。
例句：The opposing team was thoroughly crushed in the final match.（在决赛中，对手球队被彻底打败了。）
soundly defeat：“soundly”有“彻底地、稳固地”意思，突出胜利的坚实和彻底性。
例句：Our team soundly defeated the rivals.（我们队彻底打败了对手。）