Noah Webster's Dictionary 1. (a.) Having, or proceeding from, due authority; entitled to obedience, credit, or acceptance; determinate; commanding. 2. (a.) Having an air of authority; positive; dictatorial; peremptory; as, an authoritative tone.

Multi-Version Concordance Authoritative (2 Occurrences) 2 Corinthians 10:10 For they say "His letters are authoritative and forcible, but his personal presence is unimpressive, and as for eloquence, he has none." (WEY) Ecclesiastes 8:4 The word of a king has authority; and who may say to him, What is this you are doing? (See NAS)