Other forms: puissantly
Puissant means powerful and in possession of authority, and is often used to describe the political power of someone, like a prince or president.
Said the English poet, historian, and arguably puissant scholar John Milton, “Methinks I see in my mind a noble and puissant nation rousing herself like a strong man after sleep, and shaking her invincible locks.” Synonyms for this somewhat rarely used adjective include forcible, mighty, strong, steady, unyielding, and vigorous.