a gesture in which the palm of one’s hand is brought to one’s face as an expression of dismay, exasperation, embarrassment, etc.:I’m pretty sure said friend now thinks Anne and I are dating—facepalm!you have to see this one to believe it—it definitely merits the double facepalm
verb
[no object]
bring the palm of one’s hand to one’s face as an expression of dismay, exasperation, embarrassment, etc.:did anyone else facepalm during this scene?
facepalm in other Oxford dictionaries
Definition of facepalm in the US English dictionary