not
1 Americanadverb
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(used to express negation, denial, refusal, or prohibition).
You must not do that. It's not far from here.
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U.S. Slang. (used jocularly as a postpositive interjection to indicate that a previous statement is untrue).
I just love working overtime without pay. Not!
idioms
noun
adverb
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used to negate the sentence, phrase, or word that it modifies
I will not stand for it
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( in combination )
they cannot go
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Also (archaic): not but what. (conjunction) which is not to say or suppose that
I expect to lose the game — not that I mind
combining form
Etymology
Origin of not
First recorded in 1275–1325; Middle English; weak variant of nought
Explanation
The adverb not is used for negation. Do you like drinking cod liver oil? No, I do not like drinking cod liver oil. Not is a powerful word. When Hamlet says "to be or not to be," he is questioning whether he should live or die, the inverse of living. Just be careful of what's called a "double negative," where you use not with another negating word and end up negating your negation. If you say you don't know nothing about something, that means you do know something. Not is often contracted as in don't, or isn't.
Vocabulary lists containing not
Spelling Practice, Unit 8
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Spelling Practice 1, Unit 3
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
As worry mounts about the closure of this strategic waterway causing growing economic shocks worldwide, it's becoming clear this is not a short-term crisis to be resolved in a day.
From BBC • Apr. 19, 2026
Iran, however, had not yet confirmed it would attend the talks.
From MarketWatch • Apr. 19, 2026
“Trust in institutions is waning, and that’s not a problem we can brush aside. For higher education to serve the public good, we need the public’s trust.”
From The Wall Street Journal • Apr. 19, 2026
What our undercover voters are served by the algorithm is not a complete picture of what real Welsh voters are seeing online.
From BBC • Apr. 19, 2026
“That is the lead singer of Not Your Wild West Show. They’re not only rez famous, but almost actually famous!”
From "Legendary Frybread Drive-In" by Cynthia Leitich Smith
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.