Fall on your sword 的字面意思是“摔倒在自己的剑上”，实际要表达的含义是某人为一组人的行动造成的不良后果承担责任。

例句

He doesn't think he's to blame – but he's falling on his sword anyway.

She's going to resign - she's falling on her sword even though it's not her fault.

He is the boss – it's only right he's falling on his sword this time.

请注意

另一个意思相似的短语是 to take some flak - 受到很多批评。

例句

She always takes some flak for things. Even when it's not her fault.