under no circumstances
At no time; never. Under no circumstances will I allow you to go to a party on a school night.
under no circumstances
and not under any circumstancesFig. absolutely never. Andy: Under no circumstances will I ever go back there again! Rachel: Why? What happened? Sue: Can I talk you into serving as a referee again? Mary: Heavens, no! Not under any circumstances!
in/under no circumstances
used to emphasize that something should never happen or be allowed: Under no circumstances should you lend Paul any money.Don’t open the door to strangers in any circumstances. under no circumstances
In no case; never.