This is the "aged" view, also known as Crystallized Intelligence. It's what you know. It's your collection of specific skills.
We test this by measuring an agents' performance on a specific task, like playing Go, identifying images, or translating text. The problem? This is a static snapshot of ability.
This is the "younger" view, also known as Fluid Intelligence. It's not what you know, it's how fast you can learn to do new things.
This is a general ability to adapt, to generalize knowledge, and to turn experience into new skills efficiently. This is much closer to what we mean when we call a person "smart".