past master

1. N-COUNT If you are a past master at something, you are very skilful at it because you have had a lot of experience doing it. 行家; 老手[usu N 'at/in/of' n]

He was a past master at manipulating the media for his own ends. 操纵媒体为自己服务他是老手。

She is an adept rock-climber and a past master of the obstacle course. 她擅长攀岩，也是障碍超越训练场上的老手。