clannish

1. ADJ If you describe a group of people as clannish, you mean that they often spend time together and may seem unfriendly to other people who are not in the group. 自成一夥且排外的[非正式]

They were a clannish lot, not given to welcoming strangers. 他們是一夥喜好紥堆的人，不太歡迎陌生人。