Pronounced (RAY-SHIST) it is an unusual way to pronounce the word "racist" by african americans. It's a combination of poor english and use of the race card by african americans. It is more common to hear "rashis" in an imitation.
White dood: excuse me ma'am, I'm going to have to ask you to stop singing. Other students are still taking their test.
Heated Black Woman: NO, EXCUSE ME... this boy bein' rashis.
White dood: pardon me?
Heated Black Woman: Fuck you
White dood: I am going to send you to your principle.
Heated Black Woman: NO, dats rashis... there is way too much rashism in dis school.