What is the proper definition of psychopathy? I've seen all those checklists of psychopathy traits, read many articles and watched several tutorials - they mention like dozens of characteristics, but never make it clear about the actual meaning of the word.

Is psychopathy the lack of emotion? Is it the lack of empathy? What's the most accurate definition of the term?

Also, a lot of things that I've seen are unclear and contradictory:


A lot of explanations mention "disregard to social norms" as an intrinsic trait - but it clearly contradicts the trait of "self-interest", because by committing crimes or disregarding norms they harm themselves just as much as they harm people around. That's exactly what some psychopaths respond to allegations that they are dangerous and may commit a crime: "there's absolutely no reason or benefit of committing crime, so why would I do it?"
A lot of explanations mention "superficial charm", while it's unclear how do you even measure that objectively and what does it have to do with mental disorders? Is the evaluating therapist just supposed to tick "yes" next to "superficial charm" if they personally were charmed by a psychopath, or what? And what does it even have to do with mental health: it's not like "charm" is an aura directly projected by brain.
It's very unclear about impulsiveness, aggressiveness and impulsivity: some mention them as intrinsic traits of psychopathy, while others claim that they have nothing to do with it. It's also unclear how do they fit together with lack of emotional response or self interest, because they have nothing to do with each other or even contradict each other.
Things like "manipulation", "lack of realistic goals" or "disregard to safety" seem like things that 90% of the population would qualify for, at least at some point. What exactly is so special about "psychopathic" disregard for safety that makes it stand out from the disregard rutinely demostrated by every chemistry freshman? Is it like they are incapable of understanding the very concept of safety, or what? Are they not only remorseless and aggressive, but also intellectually retarded? Does there exist a negative thing that psychopaths aren't?


In short, to the question of what psychopathy means, everyone says entirely different things, most of which either don't make sense or are self-contradictory. It seems like a blanket term for everything that's considered "evil" by society, but doesn't seem like a real mental disorder. Is it even one disorder, or a collective name for several unrelated disorders?

The only thing that I am clear about is that psychopathy is innate (in comparison to sociopathy, which is trauma-induced).

P.S. I have scientific background, but I am not a psychologist - so it's possible that everything in psychology is as "vague", and I just don't understand how does this area of science works (although, for example, bipolar disorder was clear enough to me).
As the Wikipedia article on psychopathy makes clear, there are different definitions of psychpathy – and in fact there are different definitions of every scientific concept –, depending on which scholar you consult. This is not a problem, as every scientific publication will make clear which definition it uses.

The truth is that there is an ongoing discussion on what psychopathy is – and if it exists at all! It is no accident that both the International Classification of Diseases (ICD-10), which is the international standard diagnostic tool for medical and psychiatric conditions, and the Diagnostic and Statistical Manual (DSM-5), which is the international standard diagnostic tool for psychological disorders, do not contain the diagnosis psychopathy.