English Reference
adjective · noun

sustainable

adj. · n.
US /səˈsteɪnəbəɫ/ UK /səstˈeɪnəbəl/ sus·tain·able

  1. 01 B2 Upper Intermediate Academic

    adj.able to continue at the same level or rate for a long time.

    adj.capable of being maintained or continued at a certain rate or level.

    Simple

    The company's rapid growth was not sustainable because they didn't have enough staff.

    In context

    Economists warned that the current level of consumer debt is not sustainable and could lead to a market correction.

    Usage

    frequently used in business and economics to describe growth or spending

    Teacher's tip

    In academic writing, this sense refers to the logic or viability of a system rather than just the environment.

    maintainableviablefeasible
    untenableshort lived
  2. 02 C1 Advanced Technical Science

    n.a source of energy that is renewable, like wind or solar power.

    n.a renewable energy source or a product derived from sustainable practices.

    Simple

    The government is investing more money into sustainables like wind and solar power.

    In context

    The transition from coal to sustainables requires significant infrastructure investment and a complete overhaul of the national grid.

    Usage

    usually used in the plural form 'sustainables'

    Teacher's tip

    This noun use is relatively recent and mostly found in technical or policy-related discussions about energy.

    fossil fuel

Usage sustainable ways · sustainable alternatives

There is no single way to transition to more sustainable livestock farming globally.

Phys.org· 15 Aug 2026

This discovery could have cost-effective and sustainable applications in future electronic devices and other technologies.

Phys.org· 15 Aug 2026

From sustain + -able.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Common
Updated