Punish the ringleader severely as a warning to those who would copy him.
Tips
usage
Almost always appears in the formal legal/administrative phrase 以儆效尤 ("as a warning to those who would copy the wrongdoing"). Standalone 效尤 is rare and literary.
mistakes
尤 here means "fault/wrongdoing," not its more common modern meaning "especially." 效 is "to imitate," not "effective." The whole phrase is therefore "imitate the wrongdoing," not "especially effective."
