authoritative
adjective
1. having authority or ascendancy or influence
- the captain's authoritative manner
Similar word(s): influential, important
2. of recognized authority or excellence
Similar word(s): standard, definitive
3. sanctioned by established authority
- an authoritative communique
Similar word(s): official, authorised, authorized
Sentences with authoritative as an adjective:
- The authoritative rules in this school come not from the headmaster but from the aged matron.
- This book is the world's most authoritative guide to insect breeding habits.
- He instructed us in that booming, authoritative voice of his.