A famous Arabic word common between classical and spoken used in most of Arab countries. Habibi is either a friend, a boy/girl friend, husband or wife, a relative, or a familiar person to you whom you like in different way. Even if you are calling a person of the same gender, you may use it.
I, being a boy, can call my male friend, Habibi... Long time no see!
I just want to add, as is often the case, Hebrew has the same or similar word. In Hebrew, habibi means, my beloved, and has come to mean that, in a more relaxed way. either like myboo, or my homes, whatever.
It's one of many many shared words in the two languages.