negation

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

You get the negation of a proposition if you insert "not" (or some equivalent expression) into it in such a way as to form a contradictory of it.

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’.