face seem exceptionally lively and intense?

[Jamal.sh]

Hello everyone.
I'm reading How Do You Live? by Genzaburo Yoshino.

His uncle made a face as if to say he didn’t understand. At that,
Copper spoke quickly, in a pronounced voice. “People, Uncle—they
really are molecules, aren’t they? Today I really started to believe that.”
Under the dim light of the car, his uncle widened his eyes in surprise.
Didn’t Copper’s face seem exceptionally lively and intense?

Intense has many synonyms and I don't know which one suits there. Would you please tell me what intense means in the above? Serious,....?
Thanks 🙏

 

[lingobingo]

It doesn’t have a direct snynonym in that use. Intense is the only adjective that fully conveys intensity (strength/depth) of feelings/emotion.

Presumably this is a translation, but “a pronounced voice”?!

 

[Jamal.sh]

Thanks 🙏