| No. | Item | Definition |
|---|---|---|
| 1. | abyssal | deep and unfathomable |
| 2. | ambiguous | open to more than one meaning |
| 3. | anonymous | without a known identity |
| 4. | arcane | known by very few |
| 5. | baffling | completely confusing |
| 6. | behind closed doors | done in private secrecy |
| 7. | bewildering | very confusing or puzzling |
| 8. | bizarre | very strange or unusual |
| 9. | bottomless | seemingly without limit |
| 10. | brooding | darkly thoughtful or threatening |
| 11. | cagey | careful to avoid giving details |
| 12. | clandestine | kept secret or hidden |
| 13. | cloaked | hidden or covered |
| 14. | closemouthed | unwilling to talk freely |
| 15. | convoluted | complex and hard to follow |
| 16. | covert | hidden and secret |
| 17. | cryptic | having a hidden meaning |
| 18. | dark | gloomy, secretive, or evil |
| 19. | dim | faint or not clear |
| 20. | disguised | made to look different |
| 21. | dreamlike | resembling a dream |
| 22. | dubious | not to be relied on |
| 23. | dusky | darkened by fading light |
| 24. | eerie | strange and frightening |
| 25. | elusive | hard to find or grasp |
| 26. | enigmatic | full of puzzling mystery |
| 27. | equivocal | uncertain or ambiguous |
| 28. | ethereal | delicate and unearthly |
| 29. | expressionless | showing no clear emotion |
| 30. | faceless | without clear identity |
| 31. | fantastic | strange and imaginative |
| 32. | foreboding | suggesting something bad ahead |
| 33. | furtive | secretive and sly |
| 34. | ghostly | like a ghost |
| 35. | grim | dark and forbidding |
| 36. | guarded | careful and secretive |
| 37. | haunting | lingering in a ghostly way |
| 38. | hazy | vague or indistinct |
| 39. | hidden | kept out of sight |
| 40. | impassive | showing little emotion |
| 41. | impenetrable | impossible to understand fully |
| 42. | indefinable | hard to describe exactly |
| 43. | indeterminate | not exactly known |
| 44. | inexplicable | unable to be explained |
| 45. | inscrutable | impossible to read or understand |
| 46. | insubstantial | lacking solid reality |
| 47. | knotty | difficult to solve |
| 48. | labyrinthine | complicated like a maze |
| 49. | latent | present but hidden |
| 50. | macabre | disturbingly connected with death |
| 51. | masked | concealed or disguised |
| 52. | murky | dark, gloomy, or unclear |
| 53. | mysterious | hard to understand or explain |
| 54. | mystic | spiritually mysterious or symbolic |
| 55. | mythic | legendary and mysterious |
| 56. | nameless | without a known name |
| 57. | nocturnal | active or happening at night |
| 58. | numinous | spiritually mysterious and powerful |
| 59. | obscure | not clear or well known |
| 60. | occult | involving hidden supernatural forces |
| 61. | odd | strange or unusual |
| 62. | ominous | threatening or foreboding |
| 63. | opaque | not transparent or clear |
| 64. | oracular | mysteriously wise or obscure |
| 65. | otherworldly | strange and not earthly |
| 66. | peculiar | unusual or strange |
| 67. | perplexing | causing confusion or uncertainty |
| 68. | phantom | ghostlike or unreal |
| 69. | portentous | significant and ominous |
| 70. | prophetic | suggesting knowledge of future |
| 71. | puzzling | difficult to understand |
| 72. | queer | strange or odd |
| 73. | questionable | doubtful or uncertain |
| 74. | reticent | not revealing much |
| 75. | riddlelike | resembling a riddle |
| 76. | riddling | full of puzzling questions |
| 77. | secretive | inclined to conceal information |
| 78. | shadowy | dim, vague, or secretive |
| 79. | shrouded | covered or hidden from view |
| 80. | sinister | suggesting evil or harm |
| 81. | spectral | ghostly or haunting |
| 82. | stealthy | quietly secretive or sneaky |
| 83. | strange | unusual and hard to explain |
| 84. | supernatural | beyond natural explanation |
| 85. | surreptitious | done secretly and quietly |
| 86. | taboo | socially forbidden or avoided |
| 87. | tenebrous | dark, shadowy, and obscure |
| 88. | tight-lipped | refusing to reveal information |
| 89. | unanswered | still lacking explanation |
| 90. | uncanny | strangely unsettling or eerie |
| 91. | unclear | not easy to understand |
| 92. | undisclosed | kept secret |
| 93. | unfathomable | too deep to understand |
| 94. | unknown | not known or identified |
| 95. | unrevealed | not made known |
| 96. | unsolved | not yet explained |
| 97. | vague | not clearly expressed |
| 98. | vaporous | insubstantial or vague |
| 99. | veiled | partly hidden from view |
| 100. | weird | very strange or uncanny |
