1. To be located inside something: The spare keys are in the glove compartment.
2. To have been put or have come inside: You can close the door now; the cat is in.
3. To have successfully become a part or participant: The baseball team struggled to make the playoffs, but now they are in.
4. To have been elected or appointed to a political office: The current administration is in for at least one more term.
5. To be a consenting participant: The old bank robbers showed the young thief their plans and asked whether he was in.
6. To be fashionable or trendy: Narrow ties were in during the early 1960s and early 1980s.
7. be in for To be subject to something imminently: If you haven't read her books before, then you are in for a great surprise. Those dark clouds make me think that we are in for some wet weather.
8. be in for To participate in an activity, offering or risking something on its behalf: As far as painting the house goes, we are in for a day's work, but no more. We all placed our bets, and I was in for $10.
9. be in on To be aware of or to participate in some information shared with others or some group activity: I am not in on their plans, so I don't know what they are going to do. Are you in on our secret?
10. be in with To be on good terms with someone, especially with a group, to one's potential advantage: Although he is poor, he is in with the rich crowd and always goes on expensive trips with them.