deadpan face; expressionless face; po-faced
Describes a face as blank and emotionless as a Noh mask. Often used for someone hiding their feelings or showing no reaction.
With his deadpan face, I can't tell what he's thinking.
She heard the news with an expressionless face.
A set phrase combining 能面 (Noh mask) + のような (like) + 顔 (face). The expression draws on the traditional image of Noh masks, which are carved with fixed, subtle expressions.