unsustainable
adj. B2 Upper Intermediate US //ˌənsəˈsteɪnəbəɫ// UK //ʌnsəstˈeɪnəbəl// un·sus·tain·able
adj. describing something that cannot continue for a long time because it uses too many resources or causes damage.
adj. incapable of being maintained at the current rate or level; specifically relating to practices that deplete natural resources or exceed economic capacity.
The current level of spending is unsustainable for our family.
Environmentalists argue that our reliance on single-use plastics is unsustainable and will lead to a waste crisis.
The rapid expansion of the tech bubble was fueled by unsustainable debt levels that eventually triggered a market correction when investors demanded actual profitability.
Usage
Often used predicatively after 'be' or 'become'; frequently modifies nouns like 'growth', 'development', or 'debt'.