befitting or characteristic of those who inclined to social exclusiveness and who rebuff the advances of people considered inferior characteristic of a clan especially in being unified; "clannish loyalty
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. They were a clannish lot, not given to welcoming strangers. = cliquey. a group of people who are clannish are very close to each other, and seem unfriendly towards strangers
Of or pertaining to a clan; closely united, like a clan; disposed to associate only with one's clan or clique; actuated by the traditions, prejudices, habits, etc