Meaning:

“王” means “king,” and “炸” means “bombing.” Chinese card players often call Jokers “kings,” which in most games are the biggest cards in a deck. In the popular online game “QQ Landlords,” when someone puts forward a Joker, the system will automatically say “王炸,” which is now widely used as a metaphor for “turn up trumps.” In other words, it means to “do what is necessary to make a particular situation successful, especially when this is sudden or unexpected.”

Example:

A: 房价涨得那么厉害，不知道政府还有什么办法?

Fángjià zhǎng de nàme lìhài, bù zhīdào zhèngfǔ hái yǒu shénme bànfǎ?

Housing prices have soared drastically. Is there anything the government can do?

B: 增加土地供给是让房地产降温的王炸。

Zēngjiā tǔdì gōngjǐ shì ràng fángdìchǎn jiàngwēn de wángzhà。

To cool down the real estate market, they have to turn up trumps and increase land supply.

(Edited by Stephanie Yang)