General meaning:
* Eternal: This implies lasting forever, without beginning or end.
* Endless: This simply means having no limit or end.
* Infinite: This implies a quantity that is boundless and immeasurable.
* Perpetual: This suggests something that continues indefinitely.
* Everlasting: This emphasizes the duration of something, suggesting it will never cease.
More specific meanings:
* Unending: This emphasizes the lack of a final point or limit.
* Incessant: This implies something that is continuous and without interruption.
* Immutable: This suggests something that is unchanging and therefore has no end.
* Indefinite: This means something that has no specified or determined end.
The best word to use will depend on the specific context and the nuance you want to convey.