NiNis are the youth segment of the population 16-35 that neither study nor work (Ni estudian, Ni trabajan). They are the Spanish and Latin-American equivalent of the slacker. They typically live at home with their parents or other family and are sometimes referred to as leeches on family resources.
I posit that the NiNis like the slackers before them are mislabeled as lazy by society and incorrectly perceived as leeches or drains on normal society.
Slackers were of my generation. Smart people that seemed unable to focus and apply themselves to take work seriously; they spent a lot of their time on seemly wasted hobbies like video games, making videos, or writing blogs (many of which are now rather decent careers). But thinking of them as lazy is wrong. These are people that want to work, sometimes desperately, but they just don't see the point. They're not lazy, just unmotivated.
I recently got Jane McGonigal's book 'Reality is Broken' and I agree with her. It is broken. And for this youth generation reality seems pointless to engage. If we want to deal with the NiNis we need to change that.