If you receive a rebuke, it means that you have been reprimanded, or scolded. You're sure to get a rebuke if you forget to do your math homework four days in a row.
The word rebuke can be a verb, meaning to sternly reprimand or scold, but it can also be a noun, because a rebuke is the result of being scolded. The root comes from the Old French rebuchier and means "to hack down," or "beat back." A rebuke, then, is meant to be critical and to chide — in today's terms, a rebuke is verbal smack-down!