The concepts of introversion and shyness are often confused as similar, and it has much to do with their opposites. The opposite of a shy person is someone outgoing, and the opposite of an introvert is an extrovert. Both extroverts and outgoing people make friends easily, and for this reason, most people think being shy is the same as being an introvert. But it’s not.
An introvert is a person who likes to be alone; that doesn’t mean they are shy. In social situations, introverts tend to get over-stimulated and therefore need time alone to regain energy, process their emotions and thoughts.
On the other hand, shyness comes from fear. Most shy people are afraid of being evaluated negatively and thus tend to avoid social interactions. While some introverts are shy, not all introverts are afraid of negative evaluation.