noun
feigned ignorance; pretending not to know; ignoring
Describes the act of deliberately ignoring someone or something, often by pretending not to notice. Commonly used in the phrase 知らぬ顔をする.
See also: 知らん顔
彼は私を見ても知らぬ顔をした。
He pretended not to know me even though he saw me.
困っている人
Even when someone is in trouble, many people pass by with feigned ignorance.
noun
unconcerned air; indifference; nonchalance
Refers to an attitude of not caring or being indifferent, often shown by a blank or unconcerned expression. Can overlap with sense 1 but emphasizes the emotional state rather than the act of ignoring.
彼女は何があっても知らぬ顔で座っている。
No matter what happens, she sits there with an unconcerned air.