authoritative Meaning, Definition & Usage

  1. adjective satellite having authority or ascendancy or influence
    important.
    • an important official
    • the captain's authoritative manner
  2. adjective satellite of recognized authority or excellence
    definitive; classical; classic.
    • the definitive work on Greece
    • classical methods of navigation
  3. adjective satellite sanctioned by established authority
    authorised; authorized.
    • an authoritative communique
    • the authorized biography

WordNet

Au*thor"i*ta*tive adjective
Definitions
  1. Having, or proceeding from, due authority; entitled to obedience, credit, or acceptance; determinate; commanding.
    The sacred functions of authoritative teaching. Barrow.
  2. Having an air of authority; positive; dictatorial; peremptory; as, an authoritative tone.
    The mock authoritative manner of the one, and the insipid mirth of the other. Swift.
    -- Au*thor"i*ta*tive*ly, adv -- Au*thor"i*ta*tive*ness, n.

Webster 1913