The Collaborative International Dictionary of English v.0.48:

decentralizing \decentralizing\ adj. prenom.
   causing a dispersion or movement away from the center; --
   used especially of power or administrative functions.
   Opposite of centralizing.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

decentralizing
    adj 1: tending away from a central point [syn:
           decentralizing(a), decentralising(a)] [ant:
           centralising(a), centralizing(a)]