“非正式”的意思是不正式、不官方，比如朋友之间的聊天或者轻松的场合。

"非正式" means not formal or official, such as chatting between friends or relaxed occasions.

我们常用它来说不那么严肃的会议、活动或者说话方式。

We often use it to describe less serious meetings, events, or ways of speaking.