prerogative
C1Substantiv/US /prɪrˈɑɡətɪv/ prĭr-ÄG-ət-ĭv; UK /prɪrˈɑɡətɪv/ prĭr-ÄG-ət-ĭv/
An exclusive or peculiar privilege; prior and indefeasible right; fundamental and essential possession; -- used generally of an official and hereditary right which may be asserted without question, and for the exercise of which there is no responsibility
