What is an introvert or an extrovert?

Short answer
Just euphemism to define picky people.

Long answer
This post is for me to know more about “what is an introvert or extrovert”. Please note — I know “what they do”. I wish to know “what they are”.

Situation — There are bunch of people who are ear fucking with Suresh. Suresh walks out or just stands without speaking a word. How can I know if Suresh is introvert?

Possibility with Suresh is

1. He is not interested in the conversation
2. He finds the conversation to be boring
3. He is into the conversation but has nothing to say
4. Has something to say, but chooses not to talk
5. Has something to say, but lacks confidence or is not comfortable
6. He is into the conversation, but realises that there is something more interesting he can think about, so doesn’t talk
7. He is into the conversation, but dislikes people
8. He is into the conversation, but nobody has ever heard him, so he refuses to talk
9. He just hates talking (which means he never talks with anybody, not even 1 or 2 close friends, wife, children, mother, father. In this case he should consult a psychiatrist)
10. He thinks that ear fuckers are idiots
11. If this pattern is repeated 100 times, should we label Suresh as introvert. (Majority wins?)-Sigh
12. Appreciate your input of more possibilities…

For me; As per my knowledge and experience till date, I find them to be just picky in whom they wish to talk. Because man is a social animal.