素知らぬ顔

そしらぬかお

pretending not to recognize (recognise), feigned ignorance

知らん顔

しらんかお

unconcerned air, indifference, feigned ignorance, pretending not to recognize (somebody)

誰知らぬ

だれしらぬ

nobody knows

見知らぬ

みしらぬ

strange, unfamiliar, unknown

素知らぬ

そしらぬ

feigned, pretending

知らぬ存ぜぬ

しらぬぞんぜぬ

complete ignorance (usu. in reference to feigning); lack of knowledge

抜からぬ顔

ぬからぬかお

shrewd face, knowing look

知らぬが仏

しらぬがほとけ

Ignorance is bliss

知らぬ間に

before one knows it; before one realises; without one's knowledge; without noticing

見も知らぬ

みもしらぬ

completely unknown (usu. of people); unfamiliar; complete (stranger)

物知り顔

ものしりがお

a knowing look

顔見知り

かおみしり

acquaintance

訳知り顔

わけしりがお

know-it-all airs, I-know-how-it-is look

浮かぬ顔

うかぬかお

long face, looking dejected

素知らぬ振り

そしらぬふり

pretending not to recognize, pretending not to recognise, feigned ignorance

人知れぬ

ひとしれぬ

secret, hidden, unseen, inward

底知れぬ

そこしれぬ

bottomless

数知れぬ

countless; innumerable

何食わぬ顔

なにくわぬかお

innocent look, nonchalant look, air of innocence