past mistress
noun
: a woman who is proficient or thorough in some particular respect : adept
a past mistress of storytelling 
Newsweek
Newsweek
Word History
Etymology
past (as in past master) + mistress
- counterpart
- counterparts
- counterparty
- counterpassant
- counterpersons
- counterpetition
- counterpetitioned
- counterpetitioning
- counterpetitions
- counterpicket
- counterpicketed
- counterpicketing
- counterpickets
- counterplan
- counterplans
- counterplay
- counterplayers
- counterplays
- counterplea
- counterpleaded
- counterpleading
- counterpleads
- counterpleas
- counterplot
- counterplots