Sober

When I went to a bar for Jiwon's party,my friend's birthday, I met Lian, an American guy. We drank a lot of beers, sakes, and sojus. He asked me "Are you O.K.?" "Are you sober?" Actually, I did not understand the word, just smailing, at that time, so I asked that when we went to go each other's house. "What is the meaning of sober?" He expained kindly the word. He thought the word is some kind of slang. The meaning of the word is not drunken. If you are sober, you can drink the alcoholic liquors more. :)