baronEnglishOxford American Thesaurusbaron noun 1 historical the French supported the barons against King John: noble, nobleman, aristocrat, peer, lord. 2 a press baron: magnate, tycoon, mogul, captain of industry, nabob, grandee, mandarin; industrialist, proprietor, entrepreneur, executive, chief, leader; informal big shot, bigwig, honcho; North American, informal big wheel; derogatory fat cat. ▷antonyms small fry.