Translation guide
How to express pretending not to know something in Japanese, from casual to formal situations.
He pretended not to know about it.
Please don't pretend not to know.
Casual, often used when someone ignores something obvious. '知らん' is a colloquial contraction of '知らない'.
She pretended not to know me even when she saw me.
To play dumb, feign ignorance. Often used when someone is being evasive or pretending not to understand.
Don't play dumb, you know, right?
To insist that one doesn't know, often in a defensive or stubborn way.
He insisted to the end that he didn't know.
Specifically ignoring or acting as if you don't recognize a person.
Feigning ignorance about a specific subject or information.
Emphasizes knowing nothing at all about the matter.
He pretended to know nothing about the plan.
Pretending not to have heard about something, often used when someone brings up a topic you want to avoid.
知らないふり is standard and can be used in any situation. 知らんぷり is more colloquial and often implies a deliberate, sometimes rude, ignoring of something obvious.
The child pretended not to know when he was about to be scolded.
Do not directly translate 'pretend not to know' as 知らないことを装う (しらないことをよそおう). While grammatically possible, it is unnatural. Use 知らないふりをする instead.
He passed by with an innocent look, pretending not to know.
I pretended not to have heard that rumor.