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)

A denial of knowledge, relationship, and/or responsibility towards something (or someone).

* 1809 —

Whatever pleas may be urged for a disavowal of engagements formed by diplomatic functionaries in cases where by the terms of the engagements a mutual ratification is reserved, or where notice at the time may have been given of a departure from instructions, or in extraordinary cases essentially violating the principles of equity, a disavowal could not have been apprehended in a case where no such notice or violation existed, where no such ratification was reserved, and more especially where, as is now in proof, an engagement to be executed without any such ratification was contemplated by the instructions given, and where it had with good faith been carried into immediate execution on the part of the United nations.