unemployment

Un-employment, in the US anyway, generally means you were employed, but you're not now. There is something here called unemployment monies that people are paid if they become without employment, through no fault of their own. Under-employment, you would think would mean you're employed, but in the US anyway, I've seen it mean that you are employed at a level under which you are not really making enough money to live. People who are under employed often make minimum wage and have difficulty paying all their bills and buying food or fuel for heat, too.