Meaning:

“人” means “person,” “设” means “design,” and “崩塌” means to “crumble.” This term, often used to describe celebrities, refers to the scenario where a person’s public image doesn’t go well with his or her temperament or a person destroys his or her public image with a scandal.

Example:

A: 这几天你看娱乐新闻了吗？

Zhè jǐtiān nǐ kàn yúlè xīnwén le ma?

Have you checked out entertainment news of the past few days?

B: 没，有什么八卦？

Méi, yǒu shénme bāguà?

No. What’s up?

A: 某男演员婚内出轨导致居家好男人的人设崩塌。

Mǒu nán yǎnyuán hūn nèi chūguǐ dǎozhì jūjiā hǎonánrén de rénshè bēngtā。

Some actor was found cheating on his wife, totally destroying his public image as a good family man.