Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun past_master

2 senses of past master

Sense 1
past master -- (someone who was formerly a master)
       => master, professional -- (an authority qualified to teach apprentices)

Sense 2
past master -- (someone who has long and thorough experience in a given activity)
       => expert -- (a person with special knowledge or ability who performs skillfully)