Oxford Dictionary English unsustainable adjectiveadjective BrE BrE//ˌʌnsəˈsteɪnəbl// ; NAmE NAmE//ˌʌnsəˈsteɪnəbl// Add to my wordlistjump to other resultsthat cannot be continued at the same level, rate, etc. unsustainable growth opposite sustainableSee unsustainable in the Oxford Learner's Dictionary of Academic EnglishSee unsustainable in the Oxford Advanced American DictionaryCheck pronunciation: unsustainable oxfordlearnersdictionaries.com