Supremacy
noun
If you attain above it means you're up above everyone, and you're looking down on them. You have supremacy.
しじょう
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
彼は名門大学を主席で卒業した頭のいい男性なんでしょうが、明らかに白人至上主義者なのでそこが嫌いなんですよ。
He may be a smart guy who graduated at the top of his class from an elite university, but he is obviously a white supremacist and I hate that.