adj. 25B6; adjective
authoritative information : RELIABLE, dependable, trustworthy, sound, authentic, valid, attested, verifiable; accurate.
the authoritative edition : DEFINITIVE, most reliable, best; authorized, accredited, recognized, accepted, approved.
his authoritative manner : ASSURED, confident, assertive; commanding, masterful, lordly; domineering, imperious, overbearing, authoritarian; informal bossy.
unreliable, timid.