The Oxford Thesaurus An A-Z Dictionary of Synonyms - authority n.

1) power, jurisdiction, dominion, right, control, prerogative, authorization; hegemony: Who gave you the authority to tell me what to do? By the authority vested in me, I now pronounce you man and wife. 2) word, testimony, evidence, Colloq say-so: Do not accept anything solely on the authority of the Herald . 3) expert, specialist, scholar, sage, judge, arbiter: Gardner is an authority on Scottish history. 4) authorities. government, establishment, officials, officialdom, powers that be, police: The authorities lowered the speed limit.