teach (one) a lesson(redirected from teaches a lesson)
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teach (one) a lesson
To convince one to avoid some unwanted behavior in the future through the inflicting of some form of punishment or harm. Can be said of the harm or punishment itself, or the agent inflicting the harm or punishment. After the CEO was found guilty, he was forced to repay $150 million in damages and will spend the next 10 years in jail. If that doesn't teach him a lesson, I don't know what will. A: "The cat scratched Bobby this time when he pulled its tail again." B: "Well, that ought to teach him a lesson." Are you going to mess with my little brother again, or am I going to have to teach you a lesson?
teach someone a lesson
to get even with someone for bad behavior. John tripped me, so I punched him. That ought to teach him a lesson. That taught me a lesson. I won't do it again.
teach a lesson
Punish in order to prevent a recurrence of bad behavior. For example, Timmy set the wastebasket on fire; that should teach him a lesson about playing with matches . This term uses lesson in the sense of "a punishment or rebuke," a usage dating from the late 1500s. Also see learn one's lesson.