1.HBHthe part of your body that you sit on 屁股,臀部SYN bottom
2.get off your backside informalto start doing something or taking action, instead of not doing anything 起来干点事情
Examples from the Corpus
get off your backside• They should get off their backsides and let us see what they intend to do about it.• Sitting there, day in, day out, hardly able to get off his backside.
backside• Many of them needed some kind of kick up the financialbackside.• Mid-forties and creaking with crime-fatigue and cynicism, his backsidehits the bed hard.• Somehow he had landed on his backside and then had felt his tailboneknock the earth harder than was safe.• Now we were both on our backsides in the mud.