Is there a polite word that can be used to designate someone who didn't really understand what he or she was doing? Or, in general, someone who is intentionally ignorant of how things work. A "lamer" doesn't fit for being impolite, and seemingly harming some people's ears too much.
Edit: Another good definition is
It distinguishes between people who are ignorant by chance from those who are ignorant by choice.
And it makes me think that there is no polite substitution just because the meaning itself being impolite and abusive. Right?