A timesink is something that swallows large amounts of your time — usually something you did not intend to spend that time on. Social media, a video game, a badly organised meeting system, a hobby that keeps growing: any of these can be called a timesink. The tone is disapproving, but it is a soft, rueful kind of disapproval; people very often use it about themselves, half-complaining and half-confessing ('that game is such a timesink'). It is informal and fairly modern, and it lives mostly online, in gaming and in tech and productivity talk. Two useful details. It is normally used of activities rather than objects, so you say a timesink, not a time-sinking thing. And in gaming it has a slightly narrower, more neutral meaning: a part of a game designed to keep players busy for many hours without really advancing them — grinding for materials, for example — where 'timesink' is a description of the design, not always a complaint. Written timesink, time sink or time-sink; all three appear.

浪費時間的坑；時間黑洞（口語、網路用語，常帶「明知不該還是掉進去」的自嘲；電玩裡也指刻意拖時數的設計）