Any definition of intelligence that does not axiomatically say "is human" or "is biological" or similar is something a machine can meet, insofar as we're also just machines made out of biology. For any given X, "AI can't do X yet" is a statement with an expiration date on it, and I wouldn't bet on that expiration date being too far in the future. This is a problem.

It is, in particular, difficult at this point to construct a meaningful definition of intelligence that simultaneously includes all humans and excludes all AIs. Many motivated-reasoning / rationalization attempts to construct a definition that excludes the highest-end AIs often exclude some humans. (By "motivated-reasoning / rationalization", I mean that such attempts start by writing "and therefore AIs can't possibly be intelligent" at the bottom, and work backwards from there to faux-rationalize what they've already decided must be true.)