Definition of po-face in English:

po-face

Pronunciation /ˈpəʊˌfeɪs/ /ˌpəʊˈfeɪs/

noun

informal British
  • A face that is expressionless, impassive, humourless, or disapproving; a poker face.

Origin

1960s; earliest use found in Simon Raven (1927–2001), writer. Back-formation from po-faced.