expression, godan verb (-ru)
feign innocence or friendliness; hide one's true nature; play the hypocrite
Idiomatic expression describing someone who pretends to be gentle, innocent, or harmless while hiding their real personality or intentions. Often used when a normally assertive or cunning person acts meek.
See also: 猫被り
彼は上司の前では猫をかぶっている。
He plays innocent in front of his boss.
That kid seems quiet, but she's just hiding her true colors.