noun
leading aristocrat; great noble; magnate
Refers to a high-ranking noble or a powerful aristocratic family. Can be used historically or in fantasy settings. 'Boyar' is a specific historical Russian term; use only in that context.
彼は中世の大貴族の末裔だ。
He is a descendant of a medieval great noble.
その国では大貴族が政治を支配していた。
In that country, the leading aristocrats controlled politics.