| Answer | Crossword Clue |
|---|---|
| sustainable | Able to be maintained at a certain rate or level |
| unsustainable | Not able to be maintained at the current rate or level |
| untenable | (esp. of a position or view) Not able to be maintained or defended against attack or objection |
| tenable | able to be held, maintained, or defended |
| tenably | able to be held, maintained, or defended |
