I always thought that anti-social describes someone who keeps to themselves. But according to Wikipedia, anti-social is not the right word. What, then, is the correct word to describe someone who prefers to keep to themselves, avoids parties and get-togethers? I'm not looking for the absolutely precise medical term for a mental illness (because such behavior may not in fact be an illness), just an informal word.
- Where is John? Is he going out with us for dinner?
- Nah, he's probably watching Netflix in his room. He tends to be [ ].
When most people say anti-social in an informal context, are just referring to someone keeping to themselves, or are they in fact suggesting their conscience is in question (which is a symptom of the Antisocial Personality Disorder)?