The Collaborative International Dictionary of English v.0.48:

deflationary \deflationary\ adj.
   1. of or pertaining to deflation; as, deflationary signs.
      [WordNet 1.5]

   2. (Economics) associated with or tending to cause decreases
      in consumer prices or increases in the purchasing power of
      money; as, deflationary measures. Opposite of
      inflationary.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

deflationary
    adj 1: associated with or tending to cause decreases in consumer
           prices or increases in the purchasing power of money;
           "deflationary measures" [ant: inflationary]