Describes a situation where the outward appearance or stated intention is the opposite of the inner reality or true feeling. Often used in the pattern ～と裏腹に.
His words and his true feelings are opposite.
Contrary to expectations, the result was terrible.
front and back; back to back; inseparable
Rare, literal or spatial sense: two things placed back to back, or two sides of the same thing. Mostly found in older or literary descriptions.
The two houses are built back to back.
Contrary to his confident manner, he was actually very anxious inside.
I had noticed her feelings, which were the opposite of what she said.