face-palmˈface-palm verb [intransitive, transitive] informal 
to put the palm of your hand on your face, or put your face down on your hand, when you are embarrassed, disappointed, shocked at someone’s stupidity etc—face-palm noun [countable]
to put the palm of your hand on your face, or put your face down on your hand, when you are embarrassed, disappointed, shocked at someone’s stupidity etc—face-palm noun [countable]