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
Farlex Dictionary of Idioms.

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
Farlex Partner Idioms Dictionary
See also:
  • for (one's) (own) sake
  • for sake
  • be in hot water
  • wash (one's) hands of (someone or something)
  • wash hands of
  • wash one's hands of
  • wash your hands of
  • wash your hands of somebody/something
  • wash your hands of something/someone
  • keep in sight