exclusive; exclusionary; cliquish
Describes groups, attitudes, or systems that shut others out; often carries a negative nuance of being unwelcoming or insular.
あのサークルは排他的で、新入りが入りにくい。
That circle is exclusive, making it hard for newcomers to join.
排他的な態度を取ると、友達を失うよ。
If you take an exclusionary attitude, you'll lose friends.
排他主義 names the ideology or principle of exclusion, while 排他的 is the na-adjective used to describe something as exclusive in a general sense.
排他的 focuses on excluding outsiders or other groups, while 偏狭 focuses on a closed, intolerant mindset in general.
Compound of 排他 (exclusion) + 的 (-like, -ive). 排他 is from 排 (push aside, exclude) and 他 (other).