Stanford University psychology professor Robert Sutton defines an asshole as "someone who leaves us feeling demeaned, de-energized, disrespected, and/or oppressed." He wrote a new book and how to deal with assholes, called The Asshole Survival Guide.
In this Vox interview, Dr. Sutton discusses ways to manage assholes. One is trying not to care:
One of the simplest — but admittedly hardest — things you can do is simply learn not to give a shit. Not giving a shit takes the wind out of an asshole’s sails. When an asshole’s being nasty to you, ignore him.
If trying not to care about an asshole's behavior isn't good enough, then you can try tp actively shun or freeze them out:
I’m in academia, which means there are lots of assholes we can’t fire, but we can absolutely freeze them out. We don’t have to invite them to events or gatherings. We can shun them politely and smile at them as necessary, but other than that we just ignore them. That’s how we deal with assholes.
