This condition is often referred to as "introvert" or "loner".

1. "Introverts" usually refer to people who like to be alone and prefer to spend time with themselves. They are usually not social butterflies or people who like to express themselves in social situations. They prefer to gain a sense of satisfaction and achievement through their own thinking, reading, creation and other activities.

2. "Lone Ranger" refers to those who do not like to interact with others and prefer to act alone. They may like to travel alone, watch movies alone, eat alone, etc. They prefer time and space alone.