An introvert is person who is wrapped up in herself. If you are extremely shy and would rather examine your feelings in your diary than have a conversation, then you are an introvert.
The word introvert comes from Latin intro-, for inward, and vertere, for turning. It describes a person who is turned inward mentally and shows less than average interest in the outside world. Introverts often avoid social contact. The opposite of an introvert is an extrovert, who is an outgoing, gregarious person. Introvert can also be a verb, usually used in the form introverted. Sadness can make you introverted. A collapsing balloon introverts.