exterior

behind an/the ~

Behind her cheerful exterior, she was struggling with serious personal problems.

on the ~

The house needs fresh paint on the exterior before winter arrives.

bland, bluff, calm, charming, confident, cool, glacial

Despite his confident exterior, he was actually nervous about the job interview.

belie, conceal, hide

Her calm exterior concealed the anxiety she felt about the job interview.

behind sb's ~

Despite her cheerful exterior, there was deep sadness hidden behind the smile.

beneath/underneath sb's ~

Despite his quiet exterior, there was a competitive spirit underneath that drove him to succeed.