be with

verb5

1. •
   To agree with someone.

   • I came in here disagreeing, but I've changed my mind, and now I'm with you on this.
2. •
   To date or be boyfriend/girlfriend with.

   • I've been with her for almost a year now.
3. •
   To be down with (something); believe in, like, or espouse.

   • You know I ain't with using drugs.
   • You like robbing banks? Nah, I ain't with that.
4. •
   To understand someone's point or intention.

   • I'm sorry; I'm not with you on this point.
5. •
   (euphemistic) To have sex with.

   • We dated for almost a year, but I've never been with him.