# unsustainable

/ˌənsəˈsteɪnəbəɫ/ (US) · /ʌnsəstˈeɪnəbəl/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/unsustainable
Updated: 2026-05-08

## Definition

describing something that cannot continue for a long time because it uses too many resources or causes damage.

For teachers: incapable of being maintained at the current rate or level; specifically relating to practices that deplete natural resources or exceed economic capacity.

## Examples

- 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 notes

- Often used predicatively after 'be' or 'become'; frequently modifies nouns like 'growth', 'development', or 'debt'.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.