They’re intelligent, not bright.
Intelligence is having knowledge (think book knowledge )
Bright is like sharp. (think street smart or think things through that are complexed)
I have friends that I consider very intelligent that are not bright. One makes $200k as an actuary but can't figure out how to talk to his kids in a way that sounds human/normal.
Intelligence is usually defined in terms of adaptability, ability to learn, solve problems, etc.