dictatorial

of or pertaining to a dictator

in the manner of a dictator, usually with callous disregard for others.

"It was chiefly on account of his father," replied the Doctor, addressing the General, "that Philimore persevered in so rigidly keeping the secret of his attachment, having been once told by him, in the language of worldly dictatorial authority, that he would sooner follow him to the grave than that he should see him marry without fortune[…]