Exclusion
noun
When you expel others, you're practicing exclusion.
排他 is usually used in the phrase 排他的 (exclusive), which is a formal word that describes a tendency to exclude or reject those who are not part of a particular group.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
日本記者クラブはかなり排他的だよ。
The Japanese press club is fairly exclusive.