1. To be sedate, confused, or disoriented; to be, feel, or seem disconnected from reality. I was really out of it after working that 16-hour shift on Saturday. I think something is bugging John because he's been really out of it lately. It's like he's walking around in a haze.

2. To be heavily intoxicated by drugs or alcohol, especially to the point of becoming unconscious, nonsensical, or out of control. I think someone might have spiked Jack's drink with some kind of drug because he's really out of it all of a sudden. Jane is a lightweight. Only one or two beers and she's totally out of it.

3. To not be aware of or knowledgeable about something; to not be included or participating in something. Said especially of a particular trend, group, or activity. My dad is so out of it. Doesn't he know that wearing socks with sandals looks ridiculous? Everyone's been playing this new Japanese card game at school, but I'm out of it because I can't afford all the accessories for it.