Dictionary.com
Thesaurus.com
Synonyms

authoritative

American  
[uh-thawr-i-tey-tiv, uh-thor-] / əˈθɔr ɪˌteɪ tɪv, əˈθɒr- /

adjective

  1. having due authority; having the sanction or weight of authority.

    an authoritative opinion.

    Synonyms:
    official
  2. substantiated or supported by documentary evidence and accepted by most authorities in a field.

    an authoritative edition of Shakespeare; an authoritative treatment of a subject.

  3. having an air of authority; accustomed to exercising authority; positive; peremptory; dictatorial.

    said with an authoritative air.

    Synonyms:
    authoritarian, dogmatic

authoritative British  
/ ɔːˈθɒrɪtətɪv /

adjective

  1. recognized or accepted as being true or reliable

    an authoritative article on drugs

  2. exercising or asserting authority; commanding

    an authoritative manner

  3. possessing or supported by authority; official

    an authoritative communiqué

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of authoritative

First recorded in 1595–1605; authorit(y) + -ative

Explanation

Speak with an authoritative tone, or no one will listen to you. Why would they, if you sound like you don't even believe in yourself? Authoritative means sure or definitive. When writing a paper, it can be useful to quote from an authoritative source, such as the encyclopedia, but you must also do enough research that you are fluent in your subject and can speak with the authoritative voice only true immersion can produce.

Keep Reading on Vocabulary.com

Vocabulary lists containing authoritative

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Authoritative estimates place the total of undocumented residents in the U.S. at about 11 million to 11.7 million.

From Los Angeles Times • Jun. 24, 2025

“We had five good — if rocky — years together, until we sort of got one another’s rhythm, because he was Mr. Cool, he was Mr. Authoritative and straight ahead,” she said.

From New York Times • Feb. 12, 2024

"Authoritative pet parents have both high expectations of their dog and a readiness to adjust their own behavior to help their dog feel comfortable, safe and supported."

From Salon • Oct. 27, 2022

“The Annotated Memoirs of Ulysses S. Grant,” edited by Elizabeth D. Samet, is everything a work of popular scholarship should be: Authoritative, thorough and compulsively readable.

From Washington Post • Dec. 18, 2018

Authoritative statistics concerning the occupations of Wellesley women are not available.

From The Story of Wellesley by Converse, Florence