Meaning:
Translated from the English term “a sunk cost,” it refers to a cost that has already been paid for and cannot be recovered in any way. Because these costs cannot be retrieved, they should not factor at all into future decisions. However, many people don’t make decisions according to reasoning and logic. Hence, another term “the sunk cost fallacy” refers to a decision that involves continuing to invest additional resources such as people, time or money into a situation due to a desire to not waste the already used, unrecoverable resources, which may lead to more waste.
Example:
A: 丽丽的男朋友明明是个渣男，为什么她不选择分手?
Lìli de nánpéngyou míngmíng shì ge zhānán，wèishénme tā bù xuǎnzé fēnshǒu?
Lili knows that her boyfriend is a two-timer. Why doesn’t she break up with him?
B: 她跟这个男生恋爱三年了，应该是舍不得自己付出的感情。
Tā gēn zhège nánshēng liàn’ài sānnián le，yīnggāi shì shěbudé zìjǐ fùchū de gǎnqíng。
She’s been in this relationship for three years. I guess she doesn’t want to see her devotion wasted.
A: 这就是沉没成本谬误。她应该及时止损。
Zhè jiùshì chénmò chéngběn miùwù。Tā yīnggāi jíshí zhǐsǔn。
This is a case of the sunk cost fallacy. She should break up immediately to cut her losses short.