Correct

精于

/ jīngyú / 
Strokes

Definition

skillful in/proficient in/adept at

Example

As a Verb

be proficient in; be good at; be keen on

1
Jīngyú
精于
zuānyíng
钻营

be good at pursuing personal gains

2
Jīngyú
精于
cǐ
此
dào
道

be skilled in this field