unsustainableun·su·stain·a·ble /ˌʌnsəˈsteɪnəbəl◂/ adjectiveadj1impossible to continue doing for any length of timeThe company’s growth strategy proved unsustainable in a slow sales environment.
The banks claim that the cost of running the system has become unsustainable.
2involving the use of materials that cannot be grown or produced againunsustainable products such as hardwoods
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