In my mind negation has a nearly infinite set of scales on which it can be applied. While you can apply negation to politics, identity, discourse, life, and many other terrains i will limit myself to two strata for examples: ontology (the study of what exists) and systems.
At the level of knowledge, truth, arguments and theory negation can mean the total denial of the principles that your opposition or a given orthodoxy is putting before you or the denial that their foundational claims are based in any reality whatsoever. Deconstruction, as one example, has been labeled the most negative of negative theologies. What this statement is meant to signal is that deconstruction operates purely on the basis of exposing the absence of foundations (the absence of a transcendental, eternal truth) behind any narrative or truth claim; that their foundations are always broken, leaking, and internally irreconcilable. Deconstruction proceeds by saying NO to everything. There is no positive (YES) statement to back absolute truths except to say that those absolutes are merely chimeras. Deconstruction functions as a tool that clears the ground of myths and debris, leaving behind a space of play in the ruins of what was taken for truth.
At a grander scale we can think negation with regard to systems: economies, forms of social organization like race or government, weather, bureaucracies of all types, or earth-wide carbon cycles. Some of these systems can be human influenced or created but many systems are para-human, post-human, or non-human (even if humans are affected by them).
Within systems theory (if not social or material reality) there is the notion that systems, which are composed of multiple and varying elements, have emergent properties. Emergent properties are dynamics or phenomena that arise within a system but are not necessarily reducible to the elements that compose that system.
In economies there are properties like interest, inflation, depreciation, value, crisis, and so on that are unhinged from any intentional creator and escape the control of the elements of which it is now one. With race we see segregation, wealth and income disparities, the very notion of identity and blood quantum, white flight and urban renewal become dynamic actors in their own right alongside these things we call Whites, Latinos, or whatever races or groupings are identified within your geographies. In global carbon cycles global warming or global climate change is said to be at thresholds where the excess of trapped heat is creating self-propelled, self-governing, or self-creating (autopoietic) processes which will not cease if humans cease introducing carbon to the atmosphere, which gives us the risks of potentially catastrophic climatic changes (from the perspective of affected humans).
In all these cases there are non-human or post-human actors that are independent of any intentional human actor, even if humans can sometimes have some minimal effect on their management and administration. They are emergent properties endemic to systems to which (human) elements of those systems must answer to, must guide their conduct in relation to, must concede their potential or desires to.
If you follow and except that the systems (theory) approach has something to say about the reality of our lives than negation in this context would involve the destruction, nullification, or obliteration of some systems in order to throw off yokes and oppose powers that are both human and post-human in their complex nature.
When looking at negation in these ways it becomes clear that the terrain in which you apply this tool, tactic or concept acts back to help determine what negation actually is, means, or does. Negation is fluid and it is mean.