vocabularian UK /və(ʊ)ˈkabjʊˈlɛəɹi.ən/US /voʊˈkæbjəˈlɛɹi.ən/adjective 1noun 1forms 1 adjective1 •Of or relating to vocabulary. noun1 •One who cultivates a large or impressive vocabulary.You might have one of these prodigious vocabularians in your house. — 2010 formsvocabularians