The Collaborative International Dictionary of English v.0.48:

Priggish \Prig"gish\, a.
   Like a prig; conceited; pragmatical. -- Prig"gish*ly, adv.
   -- Prig"gish-ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

priggish
    adj 1: exaggeratedly proper; "my straitlaced Aunt Anna doesn't
           approve of my miniskirts" [syn: priggish, prim,
           prissy, prudish, puritanical, square-toed,
           straitlaced, strait-laced, straightlaced,
           straight-laced, tight-laced, victorian]

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "priggish":
   Quakerish, Victorian, abusive, blackening, blameful, censorious,
   choicy, choosy, condemnatory, condescending, conformist,
   conscientious, contemptuous, critical, damnatory, demure,
   denunciatory, deprecative, deprecatory, depreciative, derisive,
   discriminating, discriminative, disparaging, exacting, execrating,
   execrative, execratory, fastidious, formal, formalistic, fussy,
   goody-goody, hidebound, high-hat, invective, inveighing,
   judgmental, meticulous, mid-Victorian, narrow, nit-picking,
   objurgatory, old-maidish, overmodest, particular, patronizing,
   pedantic, perfectionistic, picky, precious, precise,
   precisianistic, prig, prim, prissy, prudish, punctilious, purist,
   puristic, puritanic, puritanical, reproachful, reprobative,
   reviling, ridiculing, sanctimonious, scoffing, scrupulous,
   selective, self-complacent, self-contented, self-esteeming,
   self-loving, self-righteous, self-satisfied, sensitive, severe,
   smug, sniffy, snippy, snobbish, snobby, snooty, snotty,
   stick-in-the-mud, stiff-necked, strait-laced, straitlaced, strict,
   stuffy, uptight, vilifying, vituperative