be with somebody

be with (one)

1. To be following along with and understanding what one is saying. Whoa, slow down, I'm not with you on this. Can you start over from the beginning?
2. To share the same views as one. I'm sorry, but I'm with the boss on this one—your plan is just way too risky.
3. To be in a romantic relationship with one. She's been with her boyfriend for just six months, but they're already talking about getting married.
4. To attend to a customer. Have a seat, and I'll be with you in just a minute.

be ˈwith somebody

1 understand what somebody is saying or explaining: I’m sorry, but I’m not with you. What exactly did you mean by ‘cut and paste’?‘Are you with me?’ ‘No, you’ve lost me. Can you explain it again?’
2 be in support of or agreement with somebody: ‘What do you think, Jonathan?’ ‘I’m with Sarah on this.’
3 used to ask a customer, etc. to wait for a short time: I’m just serving this lady. I’ll be with you in a minute.
See also: somebody