Not!


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not

An interjection negating the statement one has just made and thus rendering it sarcastic. Oh, yeah, I love getting a ton of homework on my birthday weekend. Not!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

Not!

interj. Not really so! (A tag phrase added to the end of a statement, changing it from affirmative to negative. There is usually a pause before Not!, which is said on a level pitch somewhat higher than the sentence that comes before.) Of course I’m going to pay $100 a ticket to see a rock concert. Not!
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

not!

See i don't think so.
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer
See also:
References in classic literature ?
Fair mirror and true- thou liest not! Thou hast no end to gain -- no heart to break -- Castiglione lied who said he loved -- Thou true -- he false!
Thou heardst it not! -- Baldazaar, speak no more To me, Politian, of thy camps and courts.