Answer: "Introvert" and "extrovert" are antonyms.
Explanation: Antonyms are words that are opposite in meaning, while synonyms are words that are very similar in meaning. "Introvert" and "extrovert" are antonyms because they denote contrasting meanings. While "introvert" is a word used to describe someone as a shy person, "extrovert" is used to describe someone as a sociable and outgoing person. In that way, as "introvert" and "extrovert" are opposite in meaning, they are considered to be antonyms.