Stack Exchange network consists of 177 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
I think the term "malicious" is not properly defined with regards to the intent of this community (please refer to: Should asking for malicious code be on topic?).
Do key-loggers qualify as malicious?
This depends but to me it boils down to one thing:
If the scope of the question is to make a keylogger covert, then I would say it's malicious.