turn your back on somebody

Từ điển Oxford Advanced Learner 8th

turn your back on sb/sth idiom
1. to move so that you are standing or sitting with your back facing sb/sth
• When on stage, try not to turn your back on the audience.
2. to reject sb/sth that you have previously been connected with
• She turned her back on them when they needed her.
• Some newspapers have turned their backs on discussion and argument.
Main entry: ↑back_idiom