이면이 · 이면을
the other side, the hidden side, what lies behind
Example
화려한 성공의 이면에는 많은 노력이 있었어요.
Behind the glamorous success there was a lot of hard work.
Word parts
이 inside, back+면 face, side
Literally 'inner side' or 'back side' — what's behind the surface.
Good to know
Don't confuse with the ending -(이)면 'if'; this noun usually appears as ~의 이면에(는).
Related words