What's a Papist exactly? Is a papist always a Catholic who is wholly supportive of the Pope?

Must one be some sort of cleric or theologian to be considered by detractors as a papist or were every day catholic peasants and bums considered papists by people like Luther.
From my own reading of Luther, Calvin, etc., papist is a derogatory term referring to any Roman Catholic who accepts the Pope  as a legitimate authority from God during the time of the reformation. The reformers might not have spoken as harshly against Catholics in previous generations.  After all at some point in time even Luther would have regarded the Catholic church as having legitamate authority before turning away from the gospel of grace, to works:

Here is a sample quote from Luther clearly including all Roman Catholics under the term 'papist':


  First, nobody can deny that we, as well as the papists, have received holy baptism and because of that are called Christians. (Luther's Works  41.194)