Noun

(uncountable) The act of negating something.

(countable) A denial or contradiction.

* (Thomas Hardy)

But it pleased her to play on my passion / And whet me to pleadings / That won from her mirthful negations / And scornings undue.

(logic, countable) A proposition which is the contradictory of another proposition and which can be obtained from that other proposition by the appropriately placed addition/insertion of the word "not". (Or, in symbolic logic, by prepending that proposition with the symbol for the logical operator "not".)

*

(logic) The logical operation which obtains such (negated) propositions.

* {{quote-web

, date = 2011-07-20 , author = Edwin Mares , title = Propositional Functions , site = The Stanford Encyclopedia of Philosophy , url = http://plato.stanford.edu/archives/fall2011/entries/propositional-function , accessdate = 2012-07-15 }}

Although some of the logicians working in term logic have very complicated treatments of negation, we can see the origin of the modern conception in the extensional tradition as well. In Boole and most of his followers, the negation of a term is understood as the set theoretic complement of the class represented by that term. For this reason, the negation of classical propositional logic is often called ‘Boolean negation’.

Noun

(en noun)

(logic) The negation in logic.

A refusal to comply with a request.

An assertion of untruth.

Refusal to believe a problem exists

*{{quote-magazine, date=2013-06-28, author=(Joris Luyendijk)

, volume=189, issue=3, page=21, magazine=(The Guardian Weekly) , title= Our banks are out of control , passage=Seeing the British establishment struggle with the financial sector is like watching an alcoholic […].  Until 2008 there was denial over what finance had become. When a series of bank failures made this impossible, there was widespread anger, leading to the public humiliation of symbolic figures.}}

(dated, psychology) A defense mechanism involving a refusal to accept the truth of a phenomenon or prospect.

* 2007 Feb. 11, " No facts, just emotion," Washington Times (retrieved 11 June 2013):

"Denial " came out of the therapyspeak prevalent in the middle of the 20th century, especially as it was applied to confronting the reality of mortality. It was popularized as the first stage of grief, and quickly expanded to include refusal to confront any bad news or disturbing ideas.