Synonyms for Rationalisation (same or very similar meaning)
WordNet sense 1 ((psychiatry) a defense mechanism by which your true motivation is concealed by explaining your actions and feelings in a way that is not threatening):
rationalizationWordNet sense 2 (systematic organization; the act of organizing something according to a system or a rationale):
systematization, systematisationFrom the ODE community, based on WordNetadd/edit