- authoritative, important - having authority or ascendancy or influence; "an important official"; "the captain's authoritative manner"
Antonym: uninfluential (indirect, via influential)
- authoritative, classical, definitive - of recognized authority or excellence; "the definitive work on Greece"; "classical methods of navigation"
Antonym: nonstandard (indirect, via standard)
- authoritative, authorized, authorised - sanctioned by established authority; "an authoritative communique"; "the authorized biography"
Antonym: unofficial (indirect, via official)