1. 
[syn: flightiness, arbitrariness, whimsicality, whimsy, whimsey, capriciousness]
The Collaborative International Dictionary of English v.0.48:
Arbitrariness \Ar"bi*tra*ri*ness\, n.
   The quality of being arbitrary; despoticalness; tyranny.
   --Bp. Hall.
   [1913 Webster]
WordNet (r) 3.0 (2006):
arbitrariness
    n 1: the trait of acting unpredictably and more from whim or
         caprice than from reason or judgment; "I despair at the
         flightiness and whimsicality of my memory" [syn:
         flightiness, arbitrariness, whimsicality, whimsy,
         whimsey, capriciousness]