打入冷宫

打入冷宫

Literally means:

leave out in the cold palace

Actually means:

冷宫 is the part of the palace to which few people will go. If the emperor's queen or concubines lose his favor, they will be banished to Leng Gong for the rest of life and are forbidden to go outside or meet their relatives.

Metaphorically, it means consigning something to the back shelf or throwing somebody into limbo.

冷宫，冷冷清清很少有人去的宫院；皇帝的妻妾如果失去皇帝的喜爱，就被送进冷宫，一辈子呆在那里，不得外出或和亲人见面。

比喻把人或事物搁在一边，长期不用。