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]