I'm not sure this is it. If I had to give a definition for "creepy", it would be something like: "Person Y's attitude and behavior are making Person X feel personally unsafe (to some degree) around Person Y."
Both definitions are used, and plenty more besides. This is actually why bubuy's point is so important. The cluster of things that are called 'creepy' is diverse and the most useful response to given situations varies depending on what the actual situation is rather than on whether someone calls it 'creepy'.
Incidentally, your definition is weakened by focusing on preemptively applying judgement more than causal accuracy. While the intent is to convey that the person being labeled 'creepy' is responsible for the feelings of the other it actually implies that even the most lewdly inappropriate, boundary-oblivious and clingy loser is immune to being 'creepy' when their target is sufficiently physically secure, emotionally mature and psychologically self-determined. This is absurd, clearly not your intent and actually forces the 'victim' to be disempowered before they are entitled to any 'anti-creep' rights.
It is quite OK to keep assertions of 'and it is right and fitting that we hold person Y responsible in this case and use some form of sanction' out of the actual definition of 'creepy' and in the realm of policy advocation.
even the most lewdly inappropriate, boundary-oblivious and clingy loser is immune to being 'creepy' when their target is sufficiently physically secure, emotionally mature and psychologically self-determined. This is absurd
I'm not sure that it is - unless you mean that the target is unjustified in feeling physically safe, and the loser is actually posing a threat to hir. But we can still define such behavior as "creepy" by extension, since the target would actually judge themselfes as being unsafe if they were more reasonable and knowledgeabl...
One of the lessons highlighted in the thread "Less Wrong NYC: Case Study of a Successful Rationalist Chapter" is Gender ratio matters.
There have recently been a number of articles addressing one social skills issue that might be affecting this, from the perspective of a geeky/sciencefiction community with similar attributes to LessWrong, and I want to link to these, not just so the people potentially causing problems get to read them, but also so everyone else knows the resource is there and has a name for the problem, which may facilitate wider discussion and make it easier for others to know when to point towards the resources those who would benefit by them.
However before I do, in the light of RedRobot's comment in the "Of Gender and Rationality" thread, I'd like to echo a sentiment from one of the articles, that people exhibiting this behaviour may be of any gender and may victimise upon any gender. And so, while it may be correlated with a particular gender, it is the behaviour that should be focused upon, and turning this thread into bashing of one gender (or defensiveness against perceived bashing) would be unhelpful.
Ok, disclaimers out of the way, here are the links:
Some of those raise deeper issues about rape culture and audience as enabler, but the TLDR summary is:
EDITED TO ADD:
Despite the way some of the links are framed as being addressed to creepers, this post is aimed at least as much at the community as a whole, intended to trigger a discussion on how the community should best go about handling such a problem once identified, with the TLDR being "set of restraints to place on someone who is burning the commons", rather that a complete description that guarantees that anyone who doesn't meet it isn't creepy. (Thank you to jsteinhardt for clearly verbalising the misinterpretation - for discussion see his reply to this post)