Compounds of 知らぬ顔

• 知らぬ顔
  (n) pretending not to know
  feigning ignorance
• そ知らぬ顔
  (n) pretending not to recognize (recognise)
  feigned ignorance
• 素知らぬ顔
  (n) pretending not to recognize (recognise)
  feigned ignorance