unofficial

形容词 unofficial:

1. not having official authority or sanction
2. not officially established

1. But this does not rule out unofficial discussions.
   但这并不排除进行非正式的讨论。
2. He's a kind of unofficial adviser, but I'm not sure exactly what he does.
   他像个非官方的顾问，但说不好他究竟是干什麽的。