The Collaborative International Dictionary
Imperatorial
Imperatorial \Im*per`a*to"ri*al\, a. [L. imperatorius.]
Commanding; imperative; authoritative.
Of or pertaining to the title or office of imperator. ``Imperatorial laurels.''
--C. Merivale.
Wiktionary
imperatorial
a. 1 commanding; authoritative. 2 Relating to the title or office of imperator.