transitive. To make clear (what has become overcast); to brighten up.

transitive. To free from obscurity; to make clear or apparent; to brighten or clear (the face, expression, etc.); to illuminate (the mind or…

transitive. To make (a person's face, eyes, etc.) animated or lively; to light up, brighten. Also with up.

figurative and transferred. To brighten as with light; to light up (the face) with beauty, gladness, animation, etc.

transitive. Of an expression or emotion: to cause (the eyes, face, etc.) to appear more lively or animated. Frequently in passive.