To stop caring about your job so much that you no longer care if you get fired or not. Occasionally leads to hilarity in the workplace.
Billy had so much Occupational Nihilism that, for no reason, he didn't go into work one day. He did not tell anyone at the workplace that he wasn't going to come into work the day before, or the day that he failed to show up either.
Patsy's occupational nihilism gave him courage to show up to work in a cowboy hat.