"Serious" in Engpsh can be translated as "认真的" in Chinese.

The origin of the word "serious" comes from the Latin word "seriōsus," which means "important, grave, or solemn."

Example sentences in Engpsh with their Chinese translations:

He has a serious demeanor. 他表现得非常严肃。
This is a serious matter that requires our attention. 这是一件需要我们重视的严肃问题。
She took the job offer seriously. 她认真考虑了工作邀请。