xiāo shǒu shì zhòng
斩首悬示于众。
明·冯梦龙《喻世明言》第39卷:“汪革照律该凌迟处死,仍枭首示众,决不待时。”
枭首示众作谓语;指砍头示众。
cut off a person's head and hang it up as a warning to all