To have done or experienced something before. This is a set phrase that can be used without a subject. A: "I got back to my car a mere three minutes after the meter expired, and I still got a parking ticket!" B: "Ugh, been there." Don't worry so much about failing a test, we've all been there.
(I've) been there(, done that).
Inf. I know exactly what you are talking about from my own experience.; I know exactly what you are going through. John: Wow! Those sales meetings really wear me out! Jane: I know what you mean. I've been there. Sue: These employment interviews are very tiring. Bob: I know it! I've been there.