backside

Từ điển Oxford Advanced Learner 8th

back·side [backside backsides] BrE [ˈbæksaɪd] NAmE [ˈbæksaɪd] noun (informal)
the part of the body that you sit on
Syn: ↑behind, Syn: ↑bottom
•Get up off your backside and do some work!
see a pain in the arse/backside at ↑pain _n.

• Từ đồng nghĩa / Synonyms:
  buttocks, rear, back end
• Từ trái nghĩa / Antonyms:
  front, front end, forepart