Past master countable noun
The noun is usually followed by "in/of/at (something)."
Used to refer to someone who is highly skilled or extremely experienced in a particular activity.
James is known as a past master at reading people's mind.
The politician is a real past master of manipulating press and media.
He is studying postgraduate diploma to become a past master of analyzing data.
The plural form of "past master" is "past masters".
This expression most likely refers to someone who has previously held the position of master in a lodge or another organization. Although in the mid-1800s, the term "past mistress" was used to describe an exceptionally skilled woman, it is now less commonly used, with "master" being used for both sexes. [The mid-1800s]
People tend to like forbidden or illegal things just because they are forbidden or illegal.
He must have believed that stolen fruit is the sweetest, and he, therefore, cheated on his partner.