What's the difference between priggish and priggism?

Priggish

Definition:

(a.) Like a prig; conceited; pragmatical.

Example Sentences:

(1) But the nickname implies a priggishness I don't detect.
(2) The reticent, pious, even priggish character was too alien, possibly repellant, for the writer and director of the 1999 film version, Patricia Rozema, who drew on Austen's letters to fabricate another creature altogether.
(3) In his heyday as president of Tanzania - which he ruled from 1961 to 1985 - Julius Nyerere, who has died from leukaemia aged 77, was lion- ised by the liberal left of the world for his impassioned advocacy of his style of African socialism, but mauled by his critics as a priggish autocrat, whose idealism failed to deliver prosperity to his people.
(4) Read's austere outlook has been variously characterised – by friends as much as anyone – as "snobbish", "priggish" and "too obviously born to the purple".
(5) I worked with Brian Cathcart when he was a priggish, lower-middle manager on the Independent on Sunday .
(6) It's also why Labour is being so insufferably priggish about it.
(7) The central character has often been criticised as being merely functional, but it seems to me that Nicholas is very close to a portrait of the artist as a young man: his passion, impulsiveness, somewhat exaggerated notions of gallantry, occasional priggishness and big embracing spirit are so much shared with his author (who at this stage of his life frequently had to take to horseback in order to work off his undischarged surplus of élan vital) that reading the book puts us in very close proximity to the young Dickens.
(8) A shudder will go round the super-pricey London streets of St John's Wood - 14th crappiest and apparently the home of "herds of oversized jeeps" - while Winchester, only four places from the uncoveted top spot, is dismissed for "broken bottle violence on Friday nights" and the "priggish complacency of its inhabitants".
(9) In short (well, short by my standards), the content of his viral triumph is wearily predictable Oxford Union stuff and the tone is horribly priggish.