be in with someone—(coll., also: be on the in with someone) be on friendly or familiar terms with a person:
- We go along for a drink occasionally, but we’re not really in with the people staying there.
Cf.: be out with someone—(coll., also: be on the outs with someone) be no longer friendly with a person:
- He is out with his former friend and in with his former adversary.
be with someone—(coll.)
1. pay attention to what a person is saying:
- Are you still with me—or shall I go over it again?
2. support a person; back smb. up:
- If you do decide to oppose him, then we’re with you all the way!
See also: have an in with someone / have it in for someone.