Meaning:
Literally the term means to “crush with something heavy,” like in the situation where a poor stray cat gets crushed by a speeding car. Chinese netizens use the term more as a metaphor to mean someone or something is far superior to another. They say they feel “智商被碾压” (someone else is much more intelligent) or “家庭背景被碾压” (someone else comes from a much more privileged background), etc.
Example:
A: 数学怎样才能考140分？
Shùxué zěnyàng cái néng kǎo yībǎisìshí fēn?
How did you score 140 out of 150 on the math exam?
B: 少做两道填空题。
Shǎo zuò liǎngdào tiánkòng tí。
I intentionally missed two fill-in-the-blank questions.
A: 这种感觉叫智商被碾压。
Zhèzhǒng gǎnjué jiào zhìshāng bèi niǎnyā。
You make me feel like an idiot.
(Edited by Stephanie Yang)