the thing about an IQ is that all it measures is the ability to take an IQ test, and ability to take an IQ test is thought to correlate with some sort of thing

the thing about an IQ is that all it measures is the ability to take an IQ test, and ability to take an IQ test is thought to correlate with some sort of thing called intelligence, but nobody is quite sure how it relates to intelligence, what intelligence even is, or if intelligence is a single thing. Which is why the vast majority of the people who talk about IQ tests and IQ scores are people that scored highly on it and very much want it to mean something important.