It depends on the school of thought, but the common explanation is that wisdom is knowledge of Truth backed with experience. Not the kind of truth about irrelev

It depends on the school of thought, but the common explanation is that wisdom is knowledge of Truth backed with experience. Not the kind of truth about irrelevant things, but the Truth about the nature of life. And it must be backed with experience, for it's one thing to know the map and a completely different thing to have trodden that path on the map. A selfish person cannot be wise. He may know conceptually the important truth that all life is interconnected, but having never experienced that connectedness, he easily forgets this truth when his personal interests are at stake. Someone who is poisoning the river for personal gain using his power and knowledge cannot be wise because he doesn't see the whole picture in which this river returns to what he drinks and thus he is poisoning himself. Once he becomes wise, he also stops caring about himself, for that's the only rational choice in the light of wisdom.