| No. | Item | Definition |
|---|---|---|
| 1. | alarming | causing worry or fear |
| 2. | anxiety-inducing | likely to cause anxiety |
| 3. | arduous | requiring great effort |
| 4. | awe-inspiring | inspiring awe and apprehension |
| 5. | awesome | impressive and slightly frightening |
| 6. | awful | very unpleasant or frightening |
| 7. | backbreaking | requiring exhausting physical effort |
| 8. | brutal | extremely harsh or difficult |
| 9. | burdensome | heavy and difficult to bear |
| 10. | challenging | demanding effort and skill |
| 11. | chilling | causing fear or unease |
| 12. | colossal | extremely large and imposing |
| 13. | complex | not simple; difficult to handle |
| 14. | complicated | hard to understand or manage |
| 15. | crushing | overwhelmingly heavy or difficult |
| 16. | demanding | requiring much skill or effort |
| 17. | difficult | hard to do or deal with |
| 18. | dire | extremely serious and difficult |
| 19. | discouraging | making someone lose confidence |
| 20. | disquieting | causing worry or unease |
| 21. | distressing | causing anxiety or suffering |
| 22. | disturbing | causing anxiety or unease |
| 23. | draining | taking much energy or strength |
| 24. | exacting | requiring careful effort |
| 25. | exhausting | very tiring and difficult |
| 26. | fatiguing | causing tiredness through effort |
| 27. | fearsome | causing fear or respect |
| 28. | forbidding | unfriendly and intimidating |
| 29. | formidable | impressively difficult or fearsome |
| 30. | fraught | filled with difficulty or danger |
| 31. | frightening | causing fear or alarm |
| 32. | gargantuan | enormously large or demanding |
| 33. | gigantic | very large and intimidating |
| 34. | grim | serious, harsh, and discouraging |
| 35. | grinding | wearingly difficult and persistent |
| 36. | grueling | extremely tiring and difficult |
| 37. | hair-raising | very frightening or alarming |
| 38. | hairy | dangerous or difficult |
| 39. | hard | difficult to do or face |
| 40. | harrowing | extremely distressing or difficult |
| 41. | heavy | serious and hard to bear |
| 42. | Herculean | requiring enormous effort |
| 43. | horrifying | causing horror or fear |
| 44. | hostile | unfriendly and hard to deal with |
| 45. | immense | extremely large or demanding |
| 46. | imposing | impressive and intimidating |
| 47. | inhospitable | harsh and difficult to face |
| 48. | intense | extreme and demanding |
| 49. | intimidating | causing fear or loss of confidence |
| 50. | intricate | complex and hard to understand |
| 51. | jarring | shocking or unsettling |
| 52. | knotty | complicated and difficult |
| 53. | laborious | requiring long, hard work |
| 54. | looming | seeming large and threatening |
| 55. | mammoth | very large and difficult |
| 56. | massive | very large and intimidating |
| 57. | menacing | seeming likely to cause harm |
| 58. | mighty | great and formidable |
| 59. | mind-boggling | overwhelmingly difficult to grasp |
| 60. | monumental | enormous and difficult |
| 61. | nerve-racking | causing great anxiety |
| 62. | nerve-wracking | causing great anxiety |
| 63. | nightmarish | extremely frightening or difficult |
| 64. | off-putting | discouraging or unappealing |
| 65. | ominous | suggesting something bad ahead |
| 66. | onerous | burdensome and difficult |
| 67. | oppressive | weighing heavily on the mind |
| 68. | overwhelming | too great to face easily |
| 69. | panic-inducing | likely to cause panic |
| 70. | perilous | full of danger |
| 71. | perturbing | causing worry or unease |
| 72. | petrifying | making someone extremely afraid |
| 73. | problematic | difficult to deal with |
| 74. | prodigious | remarkably great in size or effort |
| 75. | rigorous | strict and demanding |
| 76. | rough | difficult or unpleasant |
| 77. | scary | causing fear or nervousness |
| 78. | severe | very difficult or harsh |
| 79. | spine-chilling | causing intense fear |
| 80. | staggering | astonishingly great or difficult |
| 81. | sticky | awkward and difficult to handle |
| 82. | stiff | very difficult or demanding |
| 83. | strenuous | requiring great physical effort |
| 84. | stressful | causing mental strain |
| 85. | taxing | requiring much effort |
| 86. | terrifying | causing intense fear |
| 87. | testing | challenging strength or ability |
| 88. | threatening | suggesting danger or difficulty |
| 89. | titanic | enormous and formidable |
| 90. | tough | hard to manage or endure |
| 91. | towering | very great or intimidating |
| 92. | trying | difficult and testing patience |
| 93. | uninviting | not encouraging approach or action |
| 94. | unnerving | making someone anxious or unsettled |
| 95. | unsettling | causing discomfort or anxiety |
| 96. | uphill | requiring persistent difficult effort |
| 97. | vast | very large and intimidating |
| 98. | wearing | tiring and difficult over time |
| 99. | worrisome | causing worry |
| 100. | worrying | causing concern or anxiety |