WordNet (r) 3.0 (2006):

reactionism
    n 1: the political orientation of reactionaries

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "reactionism":
   Bourbonism, Toryism, backwardness, conservatism, conservativeness,
   die-hardism, extreme right, extreme right wing, extreme rightism,
   know-nothingism, laissez-faireism, monarchism, old school tie,
   radical rightism, reaction, reactionariness, reactionaryism,
   rightism, royalism, social Darwinism, standpattism,
   ultraconservatism, unprogressiveness