best definition according to whom?

There is a lot of work to define intelligence, both in the context of cognitive science and in the context of AI [0].

I haven't spent enough time looking for a good review article, but for example, this article [1] says this: "Intelligence in the strict sense is the ability to know with conscience. Knowing with conscience implies awareness." and contrasts it with this: "Intelligence, in a broad sense, is the ability to process information. This can be applied to plants, machines, cells, etc. It does not imply knowledge." If you are interested in the topic the whole article is interesting and worth reading.

[0] https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&as_ylo...

[1] https://www.cell.com/heliyon/fulltext/S2405-8440(21)00373-X