What are y'alls thoughts on what 'IQ' is?

Do you buy the concept of 'IQ' as measuring some latent & innate general intellectual/cognitive capacity, some essential & real biological construct in people's heads or genes?

Or do you lean more towards a stricter, more limited conception where IQ is simply an indication of one's current relative performance on the specific narrow set of learnable paper-and-pencil cognitive skills that animate developers of IQ tests?