This is the 8253rd most frequent Chinese word.
hsien
"Hsien" (仙) refers to an immortal or transcendent being in Chinese mythology and Daoism.
In this sentence, '先 (hsien)' is used as an adverb meaning 'first,' indicating the sequence of actions.
他先去咖啡店，然后去上班。
He first goes to the coffee shop, then to work.
Here, '先 (hsien)' is used as a prefix in '先帝,' meaning 'late' or 'previous,' specifically referring to someone who has passed away.
先帝在位时，天下太平。
When the late emperor was in power, the world was at peace.
In this usage, '先 (hsien)' functions as an adverb to indicate priority or order in discussing issues.