The noun insularity refers to the quality of being isolated or detached. In fact, the word is based on the Latin word insula, for "island." The phrase "no man is an island" means that no one can be completely separate from others.
The word insularity has a sense of detachment and insulation, but sometimes the meaning is extended to mean being narrow-minded. Parents always try to protect their kids from harm, but sometimes their insularity goes too far. If you grew up in the 1950s, for example, your parents may have wanted to protect you from the evils of Elvis and rock and roll.