World Bank President Jim Yong Kim told CNBC on Thursday that the biggest concern for the world economic engine is the level of uncertainty on everything from "political outcomes" to the impact of Brexit.

"The uncertainty for us is really an issue, because it impacts directly on economies of developing countries, and almost always negatively," Kim said on "Squawk on the Street" from the sidelines of the World Bank/International Monetary Fund meeting in Washington.

Exemplified by Brexit and to some extent Donald Trump and Hillary Clinton, the notion that "the root of all evil is globalization" is a "fundamental misperception" of how the world economy works, Kim said.

He stressed the importance of trade. "All the talk on every side about looking inward — about not embracing the rest of the world, about bringing trade down — we're extremely worried because economic implications for everybody are very, very bad."

On the matter of Britain's June vote to leave the European Union, Kim said the full impact of the decision has yet to be felt, despite the initial financial market swoon and recovery.

"So Brexit, remember they haven't begun negotiating [the withdrawal] yet," he argued. "I think you're seeing a lull in the action. But once the negotiation starts, then we'll see what the real impact is. I would say that we still don't know what the impact of Brexit will be."

Recent concern over the impact of Brexit have pushed the pound to a 31-year low against the dollar.