What is Intelligence?

As far as Artificial Intelligence is concerned, what is “intelligence”? The definition I see on various sites like Wikipedia:

Intelligence has been defined in many different ways including as one’s capacity for logic, understanding, self-awareness, learning, emotional knowledge, planning, creativity, and problem solving

Merriam Webster:

  1. The ability to learn or understand or to deal with new or trying situations : reason; also : the skilled use of reason.

  2. The ability to apply knowledge to manipulate one’s environment or to think abstractly as measured by objective criteria (such as tests).

etc seem to be a bit broad and nebulous, and not necessarily what I would be thinking of if I wanted to build an AI, or evaluate the intelligence of non human life-forms.

The definition I currently go with is:

General problem solving ability.

However, I’m not sure if this is broad enough to encompass all we think of when we say “intelligence” in the context of AI, or what we would be looking for in “intelligent” life-forms. What’s a useful definition of intelligence. Broad enough to encompass all the we consider when we think intelligence, yet narrow enough to exclude particular idiosyncrasies of specific intelligent agents? A universal definition of intelligence applicable to all intelligent agents.