Meaning:

“无脑” means “brainless,” and “吹” means “to flatter, praise.” This term, coined by Chinese netizens, refers to the scenario where fans flatter or praise their idols endlessly and all the time, or someone touts something as being perfect or first-rate despite the fact that it’s not.

Example:

A: 听说电影《好莱坞往事》很精彩。你觉得怎么样？

Tīngshuō diànyǐng 《hǎoláiwù wǎngshì》hěn jīngcǎi。Nǐ juédé zěnmeyàng？

I’ve heard that “Once Upon a Time in Hollywood” is a great movie. What do you think?

B: 拒绝无脑吹，我实话实说，这部片导演的确花了很多心思，细节出彩，不过不熟悉那段历史背景的人可能并不觉得特别好看。

Jùjué wúnǎochuī，wǒ shíhuà shíshuō，zhèbùpiàn dǎoyǎn díquè huāle hěnduō xīnsī，xìjié chūcǎi，búguò bù shúxī nàduàn lìshǐ bèijǐng de rén kěnéng bìng bù juédé tèbié hǎokàn。

I don’t like to over exaggerate and tout about it. To call a spade a spade, the director did put a lot of efforts in the details, which are wonderful. But those who are not familiar with the historical backgrounds of the story may not find the movie very appealing.