rub something off

Từ điển Oxford Advanced Learner 8th

ˌrub sthˈoff (sth) | ˌrub ˈoff derived
to remove sth or to be removed by rubbing
•She rubbed off the dead skin.
•The gold colouring had begun to rub off.
• (BrE)If you write on the blackboard, rub it off at the end of the lesson.
Main entry: ↑rub_derived