a. not having official authority or sanction
s. not officially established
a. 非正式的, 非官方的
[化] 非法定的; 未入药典的
1. The unofficial meeting will take place in the cafeteria.
非正式会议将在食堂举行。
2. She received unofficial news about the job offer before it was announced.
在正式公布之前，她收到了关于工作机会的非正式消息。
3. This document is unofficial and cannot be used for legal purposes.
这份文件是非正式的，不能用于法律目的。