extravagantly adv. + Add to list US //ˌɛkˈstɹævəɡəntɫi// UK //ɛkstɹˈævəɡəntli// ex·trav·a·gant·ly SynonymsEtymology Synonyms abundantlycopiouslylavishlyprofuselyrichlyOrigin From extravagant + -ly.