capital of Antigua and Barbuda ca·pi·ta·lofantiguaandbarbuda uncommon noun 1. the capital and largest city of Antigua and Barbuda; located on the island of Antigua SynonymsSt. John'sSaint John'scapital of Antigua and Barbuda Related words Broader terms national capital Parts Antigua and Barbuda WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.