D defs.my
Entry 2 senses Webster, 1913

Authoritative

/əth-ôr'-ət-ātˌ-ĭv/ · Au·thor·i·ta·tive · IPA /əˈθɔɹɪˌteɪtɪv/
01 a. Having, or proceeding from, due authority; entitled to obedience, credit, or acceptance; determinate; commanding.
  1. 1.
    Having, or proceeding from, due authority; entitled to obedience, credit, or acceptance; determinate; commanding.
    “The sacred functions of authoritative teaching.” Barrow.
  2. 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.