resting bitch face

noun1

1. •
   (vulgar, offensive) An angry or unpleasant look that does not accurately reflect the way a person is feeling or that the person assumes when not consciously controlling their expression.

   • A brassy blonde steps forward, and you can tell by her resting bitch face, that ultra-cruel look in her eyes, that she's the one in charge of this quasi-hostage situation. — 2013