It seems to me that intelligence is best defined by your capacity to efficiently obtain the results you desire. In school, of course, this is a high test score. In life, it varies widely.
If two people desire love, that person who seeks and maintains it best, is smartest. If you are building a shed, that person is smartest who does it best and quickest. If you want a beautiful painting, that person who produces the best one is smartest. If we are dealing with music, it is the person most capable of playing it well, writing it well, or even appreciating it, if that is the task.
Clearly, IQ matters. You can’t be a doctor with a low IQ. (although that may change, with smart people choosing to pursue other careers). At the same time, there are so many realms of human endeavor where factors along the lines of “emotional intelligence” make the difference that it is foolish for ANYONE to grant themselves the “ontological status” of smart.
In fact, I reject the term genius for anyone. Perhaps genius at times, or genius in a subject at their best, but no one is smart in everything all the time, and to the extent we believe this myth, we reject the scepticism which should attend what I term the “Cult of the Expert”.