in/under no circumstances

in no circumstances

Never; in no case or situation; irrespective of events or conditions. In no circumstances are you allowed to drive home after you've had more than one drink! I'm sorry for my sudden resignation, but in no circumstances will I work for some sexist manager like him.
See also: circumstance, no

under no circumstances

At no time; never. Under no circumstances will I allow you to go to a party on a school night.
See also: circumstance, no
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

under no circumstances

 and not under any circumstances
Fig. 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!
See also: circumstance, no
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

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.
See also: circumstance, no
Farlex Partner Idioms Dictionary © Farlex 2017

under no circumstances

In no case; never.
See also: circumstance, no
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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