Synonym of "less formal"

As casual conversation simply means an idle chatter, I wanted to know of a word which means a "formal talk". Not completely formal, but rather a word for a conversation where people talk only for a purpose; a word which would mean "not casual, but less formal." This didn’t help.

Think of a person(a loner) who doesn’t like making friends but can talk with others only if the conversation holds some purpose.
What would be the word used to describe such a conversation?