The manual is terrible when it comes to cleary listing all the abbreviations used. I figured out most of the resistances, but what does NP:-10 mean? I mean, I know it is a penalty for noise, but is -10 good or bad or what? :-?
NP = Noise Penalty, as you said and as the manual says on page 115. -10 means you will be 10 units noisier than the baseline. Sneaking will be harder, and then there's the constant clanging and jingling which you may or may not find irritating. There are items which make you quieter as well.