Removing bias from IQ tests is one hell of a challenge, but if we put that aside and only analyse IQ results from people from similar backgrounds, it definitely measure something, and it usually gives accurate results. Meaning your score would not change much by taking the test again.

IQ score correlate with someone general ability in pattern recognition, languages, logic, bias check and etc. It also correlate with grades, salary, lifespan. So, is that intelligence? I don’t know, but it is something.