authoritatively

Adverb

authoritatively (comparative more authoritatively, superlative most authoritatively)

1. In an authoritative manner; with authority.
   • He has, of course, the right to speak authoritatively, and he laughs at my theory that there was a crack in Pansay's head and a little bit of the Dark World came through and pressed him to death.1888, Rudyard Kipling, “The Phantom Rickshaw”, in The Phantom 'Rickshaw and Other Tales, Allahabad: A.H. Wheeler and Co., page 8
   • The inability of Trump's own spokespeople to speak authoritatively on the president's thinking and actions -- a challenge even Trump himself has acknowledged -- has left the White House with an enormous credibility gap, and has tarnished the reputations of many of its most visible spokespeople.2017 May 16, Dylan Byers, “Does anyone in Trump's White House have credibility?”, in CNN Business, archived from the original on 22 Mar 2025