눈이 삐었다 ((he) must be blind)
눈- [n] The sensory organ on the face of a person or animal that can see an object when stimulated by the light.
삐다 - [v] have a wrick in; sprain; wrench, for a joint of a part of one's body to be twisted or bent strongly and dislocated.
semi-polite: 눈이 삐었어요
>> This expression is used to criticize someone that has made a mistake in judgment when something is clear enough to know without having to check or experience it.
>> “삐다” is a verb used when a part of the body was twisted or sprained, causing a bone joint to become misaligned, as when you sprain your ankle or wrist.
>>However, this expression is used to say someone’s judgment may be impaired when you see someone is making a wrong decision despite the outcome being so obvious.