noun
frightful face; scary face
Used to describe a face that looks frightening, stern, or intimidating. Often carries a slightly humorous or exaggerated tone.
彼は怒ると御面相が怖くなる。
When he gets angry, his face becomes frightening.
そのお面は御面相がすごい。
That mask has a really scary face.
Compound of honorific prefix 御 (ご) and 面相 (めんそう, 'face, features'). The exact origin of the 'frightful' nuance is uncertain, but it likely developed from the idea of an imposing or stern countenance.