All 4 Uses

insular
in
Moby Dick
(Edited)

There now is your insular city of the Manhattoes, belted round by wharves as Indian isles by coral reefs—commerce surrounds it with her surf.
Chpt 1-3

insular = isolated or like an island
Each silent worshipper seemed purposely sitting apart from the other, as if each silent grief were insular and incommunicable.
Chpt 7-9 *

insular = isolated and self-contained
I saw that under the mask of these half humorous innuendoes, this old seaman, as an insulated Quakerish Nantucketer, was full of his insular prejudices, and rather distrustful of all aliens, unless they hailed from Cape Cod or the Vineyard.
Chpt 16-18

insular = narrow-minded and inward-looking
For as this appalling ocean surrounds the verdant land, so in the soul of man there lies one insular Tahiti, full of peace and joy, but encompassed by all the horrors of the half known life.
Chpt 58-60

insular = island-like -- set apart and self-contained

Definitions:

(1) (insular)
interested only in the ideas and viewpoints of your culture or small group
(2) (meaning too rare to warrant focus)
related to an island