Q From Simon Field: Seeing your article on bated breath made me think of past master. Journalists seem to use it to mean a person is an expert at something. I believe this is in fact a corruption of pass muster, which is to say that the person is competent, that he or she has or would successfully pass the army training or parade in the subject. Do you have any comments?
A Past master is a puzzling idiom because of a confusion over spelling. But it’s not derived from pass muster, which means to pass an inspection of uniform and equipment at an assembly of troops, a muster.
As you say, past master often means a person who is particularly skilled at some activity or art:
Irish writer John Boyne is a past master of fictional representation of history in his novels
The Age (Melbourne), 24 Aug. 2009.
But it isn’t the only sense. Another is at least as common and about a century older. It’s the more straightforward one of a person who has previously been a master, that is, filled an office with that title. It’s most often used of a former master of a Freemasons’ lodge, although it has broader applications. As a result of the common confusion between the adjective past and the past tense and past participle passed, it’s not unknown for this second sense to be written as passed master.
That confusion is at the heart of your sense of past master. A verb to pass master once existed, which meant to graduate in a scholastic field or become qualified in a skill. In the former sense, it was linked to the higher degrees of master of arts and similar qualifications; among artisans, it meant that a man had completed his apprenticeship and his period as a journeyman and had become officially a master of his craft.
Though the verb to pass master has long since vanished from the language, the noun derived from it survives. It ought to be passed master and this spelling is known, though rare. The standard form is past master. Undoubtedly, this became accepted as a result of the existing institutional sense of past master.