1 (of an action, a decision, a rule, etc.) not seeming to be based on a reason, system or plan and sometimes seeming unfair:
The choice of players for the team seemed completely arbitrary. * He makes unpredictable, arbitrary decisions.
2 (formal) using power without restriction and without considering other people:
the arbitrary powers of officials
arbitrarily adverb:
The leaders of the groups were chosen arbitrarily. * The political frontiers in Africa were often arbitrarily drawn up by the old colonial powers.
arbitrariness noun [U]:
Court officials were suspected of arbitrariness and personal bias.
