Synonyms for authoritative

modified

1. Based on competent authority

   well-supported, well-documented, scholarly, reliable, trustworthy, authentic, dependable, definitive, sound; see also sense 2, official 3.

2. Having authority

   official, executive, imperial, administrative, supreme, ex cathedra (Latin), dominant, lawful, legal, mandatory, impressive, imposing, orthodox, ruling, sovereign, having due authority, weighty, having the weight of authority, entitled to obedience, decisive, worthy of acceptance, canonical, valid, standard, authorized; see also administrative, approved, governing, reigning.

   Antonyms unauthorized, illegal*, questionable.

3. Suggestive of authority

   dogmatic, officious, domineering; see absolute 3, autocratic 1.