П-82

КАК ПЕНЬ стоять, сидеть и т. п. highly coll , disapprov , rude when used in direct address (как + NP Invar adv may be used with pl subj) (to stand, sit etc somewhere) not saying or doing anything, not showing any interest in or understanding of what is going on etc: X стоял (сидел) как пень = X was standing (sitting) (there) like a dummy.