be sb's lookout

be (one's) (own) lookout

To be a problem or difficulty that one has caused oneself. Primarily heard in UK. If you stay up till 3 AM, it's your own lookout if you sleep through your alarm.See also: lookout

be ˈsb’s (own) lookout

(British English, informal) be somebody’s problem because they are responsible for causing it: If he wants to invest all his money in one company, that’s his lookout. ♢ It’s my own lookout if I fail this exam.See also: lookout