What's the adjective for insular? Here's the word you're looking for.
Included below are past participle and present participle forms for the
verbs insulate and insularize which may be used as adjectives within certain contexts.
insular
Of, pertaining to, being, or resembling an island or islands.
“This is why cities in which more citizens have traveled around the world are typically more beautiful and prosperous cities, and why cities whose citizens are closed-minded and insular are ugly and poor.”
“They are discovering that the abnormal city of Las Vegas allows them perhaps the most normal, nine-to-five-style schedules and insular lives that stage stars can find beyond Broadway.”
(astronomy) Situated at so great a distance as to be beyond the effect of gravitation; said of stars supposed to be so far apart that the effect of their mutual attraction is undetectable.