brightness
US /ˈbraɪt.nəs/
UK /ˈbraɪt.nəs/

1.
the quality or state of giving out or reflecting light
:
•
The brightness of the sun made it hard to see.
•
Adjust the screen brightness for better viewing.
2.
the quality of being intelligent and quick-witted
:
•
Her academic brightness was evident in her grades.
•
He always impressed everyone with his intellectual brightness.