Source : Webster's Revised Unabridged Dictionary (1913)

Arbitrarily \Ar"bi*tra*ri*ly\, adv.
   In an arbitrary manner; by will only; despotically;
   absolutely.

Source : WordNet®

arbitrarily
     adv : in a random manner; "the houses were randomly scattered";
           "bullets were fired into the crowd at random" [syn: {randomly},
            {indiscriminately}, {haphazardly}, {willy-nilly}, {at
           random}, {every which way}]