表裏
ひょうり front and back; inside and outside
Why it means this
A pair of opposites, 表 (the front) and 裏 (the back) — the two sides of a thing; 表裏一体, inseparable like two sides of a coin; 表裏がある, two-faced.
Breakdown
Each character links to its full entry — origin story, stroke order, and readings.