From Longman Dictionary of Contemporary Englishauthoritativeau‧thor‧i‧ta‧tive /ɔːˈθɒrətətɪv, ə- $ ɒːˈθɑːrəteɪtɪv, əˈθɔː-/●くろまる○しろまる○しろまるAWL adjective1BELIEVEan authoritative book, account etc is respected because the person who wrote it knows a lot about the subjectthe most authoritative work on English surnames2CONFIDENTbehaving or speaking in a confidentdetermined way that makes people respect and obey youHe has a commanding presence and an authoritative voice. —authoritatively adverbExamples from the Corpusauthoritative• The results provide the most authoritative and conclusiveevidence to date of some enduringinequities in participation in such facilities.• an authoritativebiography of Theodore Roosevelt• An authoritative energy-labelling system will assist them to do that.• A clear, authoritativestatement of the new doctrineevolving is yet to be announced.• Not very imaginative, it amounted to a genuflection to Papini and his authoritativeviews.• Bagehot's work continued to be regarded as an authoritative work long after the Constitution had undergonefundamental change.