past master

plural past masters · alternative archaic passed master · alternative past-master · alternative pastmaster

1. One who has an extremely high level of ability or knowledge within an area of achievement or expertise.

   The Hon. Morison was a past master in the art of insidious boasting.

   1915 December 4 – 1916 January 8, Edgar Rice Burroughs, chapter XVII, in The Son of Tarzan, Chicago, Ill.: A[lexander] C[aldwell] McClurg & Co., published March 1917, →OCLC, page 245

   3 more examples

   It required a deft hand and deep knowledge of the barbaric mind effectually to handle such diverse weapons; but he was a past-master in the art, knowing when to conciliate and when to threaten with Jove-like wrath.

   1900 April 7, Jack London, “The Son of the Wolf”, in The Son of the Wolf: Tales of the Far North, Boston, Mass.; New York, N.Y.: Houghton, Mifflin and Company […], →OCLC, page 24

   Hervey responded with such volubility that anyone could see he was a pastmaster in Castilian swearing.

   1907, Fergus Hume, chapter 27, in The Green Mummy

   Winterbottom is a past master at lending the traditional story-telling format to real stories of the modern world at war.

   2007 May 21, Richard Corliss, Mary Corliss, “Cannes Journal: Mighty Hearts and Dark Deeds”, in Time

   Synonyms: expert, guru, adept, ace, artist, buff, crackerjack, crack hand

2. FreemasonrySomeone who has previously been a master at a given lodge.