Richelieu ric·he·lieu US/ˈrɪʃʌˌlu/ uncommon noun 1. French prelate and statesman; principal minister to Louis XIII (1585-1642) SynonymsDuc de RichelieuArmand Jean du PlessisCardinal Richelieu Related words Broader terms archprieststatesman WordNet 2.1 (Princeton University). CMU Pronouncing Dictionary. WordNet 2.1 Copyright Princeton University. All rights reserved.