1. Lair
2. Refuge
3. Retreat
4. Shelter
5. Hideaway
6. Cave
7. Sanctum
8. Bastion
9. Stronghold
10. Bastille
11. Sanctum Sanctorum
12. Burrow
13. Nest
14. Hideout
15. Hidey-hole
16. Recess
17. Redoubt
18. Repository
19. Repose
20. Nook
21. Covert
22. Cubby
23. Cubbyhole
24. Den of Iniquity
25. Den of Thieves
26. Den of Vice
27. Lair of Iniquity
28. Hide
29. Sanctum of Mischief
30. Warren

When looking for synonyms for the word «den», there are many great ideas to consider. Whether you are looking for a word to describe a physical space or a figurative one, there are plenty of options available. Whether you are looking for a more formal word or a more casual one, there are plenty of other words for «den» that you can choose from. Some of the best ideas include lair, refuge, retreat, shelter, hideaway, cave, sanctum, bastion, stronghold, bastille, sanctum sanctorum, burrow, nest, hideout, hidey-hole, recess, redoubt, repository, repose, nook, covert, cubby, cubbyhole, den of iniquity, den of thieves, den of vice, lair of iniquity, hide, sanctum of mischief, and warren. There is no shortage of synonyms for the word «den» and the best option for you will depend on the context of your writing.