A person who prefers to be by themself. Usually of low self-confidence resulting from severe depression. May have had a hard up bringing. Never fit into a social group (i.e. Preppie, punk, goth, jock, etc.) Not influenced by trends or fads. Has more original likes/dislikes than the common over commercialized asshole running around. Likes things that require INTELLIGENCE to understand. Many would like to have social lives but are rejected by ignorant assholes that don't realize these people actually have feelings, thus putting the loner back even further in social development. Many times called a "psycho" or a "retard", when they're probably the smartest or sanest person in the room!
The loner is the one that doesn't get invited to the bar after work.