In other words, a nihilist is a "person who does not bow down to any authority, who does not accept any principle, however much that principle may be revered."
The human mind creates ethics, moral codes, rules, excuses and justifications for the deepest epiphany and the most trivial event alike.
Some even go so far as to hijack random events and misinterpret them as self-created, the psychological principle known as 'illusion of control'. Unfortunately the complexities of the human mind merely make it easier to believe in fantasy and entertain delusion.
Such an effort to find greater significance where there really is none and this only leads to wayward guidance and specious justifications. Those concocted reasons are then used to justify what need not be justified like our continued existence except based upon lies, setting up everyone for the fall when the myth erodes.
Everything would move onward quite smoothly without any human minds around to believe in good, bad and/ or any other fictions, which it did before us and it would do so after as well. Instead the Nihilist is concerned with the things that matter whether anyone believes in them or not; all those forces and factors that influence even the things that don't think.
Self-delusion may well be the defining quality of human nature. Lies maintain our flimsy order, we find consolation in myths like 'what we do has significance' and 'the bad gets punished'.
The constant avalanche of empirical evidence to the contrary simply gets relegated to the third class bureau of irrational philosophers.
In short, hypocrisy can only flourish when goodness is defined not only as kind and altruistic behavior, but as sticking to the rules as well.
Clearly we have a dilemma on our hands...
That is to say a real, mature nihilist is a very serious person with a sharp and cogent mind, but who also is dealing with a double edged sword that can just as easily lead to damage, as to enlightenment.
As humbling as it is, the scale and perhaps significance of humanity shrinks in accordance with the magnitude of our knowledge.
A basic understanding of cosmology leads to the ultimate nihilism.
Springing from a cosmic accident, we have apparently no purpose, objectives or value.
As a "practiising nihilist" [ and I hate myself for that ], I say it's our domain and we can make it a hell or a heaven. But as long as we prejudge the decision absolving ourselves of responsibility then it probably will be a realm of "mr. hot stuff".
If that's what everyone expects, then that's all it will ever be.