Inbox rot means to neither accept, nor decline a friend request from someone on social networking sites. This strategy is used in situations when you don't want to accept someone's friend request, but you also don't want to be rude by declining them.

Inbox rot指对于某人在社交网站上对你发出的加好友请求，既不接受、也不拒绝的态度。使用这种策略多半是因为，你不想接受某人的加好友请求，又不想直接拒绝对方，显得很无礼。

这里用inbox rot大概传递的意思就是，我要让你的加好友请求烂在我的收件箱里，就是不搭理你。