| No. | Item | Definition |
|---|---|---|
| 1. | acute | serious or intense |
| 2. | adult | mature and serious |
| 3. | alarming | causing serious concern |
| 4. | appalling | shockingly bad or serious |
| 5. | austere | severe in manner |
| 6. | awed | filled with solemn wonder |
| 7. | awful | very bad or serious |
| 8. | baleful | threatening harm or evil |
| 9. | bleak | without hope; grim |
| 10. | brooding | darkly serious and thoughtful |
| 11. | calamitous | bringing great disaster |
| 12. | catastrophic | extremely damaging or serious |
| 13. | charged | full of strong feeling |
| 14. | cheerless | lacking cheer or hope |
| 15. | consequential | important in effect or result |
| 16. | considerable | notably great or important |
| 17. | contemplative | deeply thoughtful |
| 18. | critical | very serious; decisive |
| 19. | damning | strongly condemning or harmful |
| 20. | dark | gloomy or threatening |
| 21. | desperate | extremely serious or bad |
| 22. | dire | extremely serious or urgent |
| 23. | disquieting | causing unease or concern |
| 24. | disturbing | causing serious worry |
| 25. | dour | stern and gloomy |
| 26. | dreadful | very bad or serious |
| 27. | earnest | serious and sincere |
| 28. | fateful | having serious consequences |
| 29. | forbidding | stern and unfriendly |
| 30. | formal | serious and official |
| 31. | fraught | filled with tension or danger |
| 32. | funereal | like a funeral; mournful |
| 33. | gloomy | dark or depressing |
| 34. | glum | gloomy and quiet |
| 35. | grim | stern and forbidding |
| 36. | grown-up | mature and serious |
| 37. | harrowing | extremely distressing |
| 38. | heavy | serious or emotionally weighty |
| 39. | high-stakes | involving serious consequences |
| 40. | horrible | very unpleasant or serious |
| 41. | humorless | not playful or funny |
| 42. | hushed | quiet and solemn |
| 43. | ill-omened | suggesting bad outcomes |
| 44. | implacable | unable to be calmed |
| 45. | inauspicious | unfavorable; unlucky-looking |
| 46. | inexorable | impossible to stop |
| 47. | intense | very serious or strong |
| 48. | joyless | without happiness |
| 49. | judicious | showing good judgment |
| 50. | levelheaded | calm and sensible |
| 51. | loaded | emotionally heavy or serious |
| 52. | major | very important or serious |
| 53. | material | important; relevant |
| 54. | mature | fully developed and sensible |
| 55. | measured | careful and controlled |
| 56. | meaty | substantial and serious |
| 57. | meditative | quietly thoughtful |
| 58. | melancholy | sad and thoughtful |
| 59. | menacing | threatening harm |
| 60. | mirthless | without humor or joy |
| 61. | momentous | very important and serious |
| 62. | morose | sullen and gloomy |
| 63. | mournful | sad and solemn |
| 64. | muted | soft and subdued |
| 65. | ominous | suggesting something bad |
| 66. | pensive | deeply thoughtful and serious |
| 67. | pitiless | without mercy |
| 68. | portentous | seriously significant; ominous |
| 69. | pressing | needing quick attention |
| 70. | profound | very deep or serious |
| 71. | prudent | careful and sensible |
| 72. | reflective | thoughtful and serious |
| 73. | relentless | harsh and unyielding |
| 74. | respectful | showing respect |
| 75. | responsible | serious and dependable |
| 76. | restrained | controlled and serious |
| 77. | reverent | showing deep respect |
| 78. | ruinous | causing great damage |
| 79. | ruthless | harsh and without pity |
| 80. | sepulchral | gloomy; hollow and solemn |
| 81. | serious | not lighthearted; important |
| 82. | severe | very serious or harsh |
| 83. | sinister | suggesting evil or harm |
| 84. | sober | serious and restrained |
| 85. | solemn | deeply earnest and formal |
| 86. | somber | dark, serious, and gloomy |
| 87. | stark | harshly serious or plain |
| 88. | stern | serious and strict |
| 89. | taut | tense and strained |
| 90. | tense | full of strain |
| 91. | terrible | extremely bad or serious |
| 92. | thoughtful | showing careful consideration |
| 93. | threatening | suggesting danger or harm |
| 94. | tragic | causing great sadness |
| 95. | troubling | causing concern |
| 96. | unsmiling | not smiling; serious |
| 97. | unsparing | harsh and severe |
| 98. | unyielding | not giving way |
| 99. | weighty | important and serious |
| 100. | worrying | causing concern or anxiety |