under no circumstances
Meaning: If you are told that under no circumstances should you do something, you must never do it, no matter what happens.
- If the red light is on outside the studio, under no circumstances is anyone to go in there. It means they're recording a song.
- This is a dangerous drug, so under no circumstances is it to be left anywhere in the hospital that members of the public could access.
Under no circumstances can this door be left open. You