Social terrorism means when someone you know comes to visit unexpectedly and inconveniently, often staying for a long time, and you can’t tell them to leave without being rude.

Social terrorism(譯為“不速之客”或“社交炸彈”)指有熟人在你不太方便的時候突然到訪，而且停留很長時間，你又不能很粗魯地要求人家離開。

例句:

Yesterday, I was just about to go out, and then the doorbell rang. It was Sally, and she invited herself in and stayed for an hour! It was social terrorism!

昨天，我正要出門的時候，門鈴響了。原來是莎莉，她也不客氣就進了屋還待了一個小時!簡直就是個不速之客!