relating to or characteristic of a person who is shy, quiet, and/or reserved in nature, especially in terms of having one's thoughts turned inward and preferring to spend time alone;
e.g. His introverted nature prevented him from making small talk with unfamiliar people.
(adjective)
broadly, turned inward in one's views, tending to focus on one's own affairs, often to the point of being narrow-minded or limited, typically describing a group or community;
e.g. She grew up in an introverted community, so she didn't learn much about people who were different from her.