Webster’s Revised Unabridged Dictionary · 1913
Authoritative
Au·thor′i·ta·tive (a̤·thŏr′ĭ·tā·tĭv), a. 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.