The Collaborative International Dictionary of English v.0.48:

Pietistic \Pi`e*tis"tic\, Pietistical \Pi`e*tis"tic*al\, a.
   Of or pertaining to the Pietists; hence, in contempt,
   affectedly or demonstratively religious. --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pietistic
    adj 1: of or relating to Pietism; "the Pietistic movement" [syn:
           pietistic, pietistical]
    2: excessively or hypocritically pious; "a sickening
       sanctimonious smile" [syn: holier-than-thou, pietistic,
       pietistical, pharisaic, pharisaical, sanctimonious,
       self-righteous]

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "pietistic":
   Christian, Christianlike, Christianly, Tartuffian, Tartuffish,
   adoring, affected, assured, believing, canting, certain, confident,
   convinced, cultish, cultist, cultistic, devoted, devout, dogmatic,
   doubtless, dutiful, faithful, false, fideistic, godly, goody,
   goody-goody, holier-than-thou, holy, hypocritical, impressed with,
   insincere, mealymouthed, persuaded, pharisaic, pious, pistic,
   positive, prayerful, religious, reverent, reverential, sanctified,
   sanctimonious, satisfied, secure, self-righteous, sniveling,
   sold on, solemn, sure, theistic, unctuous, under the impression,
   undoubtful, undoubting, venerational, venerative, worshipful