1. Infinity
2. Perpetuity
3. Endlessness
4. Immensity
5. Timelessness
6. Continuity
7. Permanence
8. Unendingness
9. Unceasingness
10. Interminability
11. Unboundedness
12. Unfathomedness
13. Uninterruptedness
14. Unmeasuredness
15. Unmeasurable
16. Unrestrainedness
17. Unconfinedness
18. Unconstrainedness
19. Limitlessness
20. Unboundedness
21. Boundlessness
22. Interminableness
23. Unendingness
24. Unceasingness
25. Uninterruptedness
26. Interminability
27. Unconstrainedness
28. Unfathomedness
29. Unmeasuredness
30. Unmeasurable

When searching for synonyms for the word ‘eternity’, there are many ideas to consider. From ‘infinity’ to ‘unmeasurable’, there are a variety of words that can be used to express the concept of eternity. Whether you are looking for the best synonyms to use in creative writing or to use in everyday conversation, these words can help you find the perfect way to express the idea of eternity. With these 30 different words, you can find the best word to fit your needs and express the concept of eternity in a meaningful and effective way.