1
: having or showing impressive knowledge about a subject
He is an authoritative [=reliable, accurate] source for information about Islamic art.
The book is an authoritative guide to the city's restaurants.
2
: having the confident quality of someone who is respected or obeyed by other people
His manner is polite but authoritative.
She addressed the group with an authoritative voice.
Cite this Entry
“Authoritative.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/authoritative. Accessed 15 Apr. 2026.
Copy Citation
