Someone who loves to be alone and enjoys spending time in solitude is often referred to as an "introvert." Introverts gain energy from being alone or in small, intimate settings, as opposed to extroverts who tend to thrive in social situations and gain energy from being around others. It's important to note that being an introvert is simply one aspect of a person's personality and does not define all aspects of their character. People can have a mix of introverted and extroverted traits.