Yist

A person who offended another person with a disability mentally or physically.

Person with disability: *walks onto the train* can I please sit on the disabled seat that your on?
A rude person: no way you mentally ill peace of sh*t.
A normal person: Hey stop being a yist and let her sit there!
Person with disability: Thank you.
A normal person: No problem, that guy shouldn't have said that.