ichidan verb, intransitive verb
feign ignorance; pretend not to know
Colloquial intransitive verb; often used when someone plays dumb or acts clueless in a casual, sometimes exaggerated way.
See also: とぼける
Even though he knew, he feigned ignorance and didn't answer anything.
すっとぼけるのはやめて、本当のことを話してよ。
Stop pretending you don't know and tell me the truth.