1. not able to be maintained or continued at the current rate or level
2. causing damage to the environment in a way that cannot continue
Usage: environmental context

Examples

• The company’s rapid growth proved unsustainable in the long term.
• Current spending levels are unsustainable and must be reduced.
• The factory’s unsustainable practices polluted the nearby river.
• Experts warn that our current energy consumption is unsustainable.
• The team’s winning streak was unsustainable without key players.
• Unsustainable fishing methods threaten marine ecosystems.
• The government’s debt has reached unsustainable levels.