A person who is shy.
a person who is socially reserved and prefers to pay attention to his or her private mental experiences. (449)
turn inside; "He introverted his feelings"
a person who is energized by solitary time, especially time spent on what he or she does inside his or her head
a person who's strength or drive comes from inside of them
a private person who needs time and space to be alone
An introverted person.