2) A good female friend. This is similar to the use of "girlfriend" by other women and gay men to mean "a good female friend." A straight man can use "ladyfriend" in this manner without the social stigma of calling a mere friend his "girlfriend." This can be compared to the word "guyfriend."
A person you met when searching online personal ads and befriended in order to introduce each other to people you know (and are not dating for some reason). Ladyfriends consider themselves the coolest people on that particular personal ad website.
"I introduced my ladyfriend to the cute guy I met on my way to work. I'd date him but he's allergic to soap and I really really love soap."
A person you are seeing, dating, or perhaps even sleeping with, but isn't technically considered your girlfriend. Somewhere between a casual date and an actual girlfriend.