| maze(noun, secret) |
| muddle |
| obstreperous(adjective, tough, problematic, trying) |
| occupation(noun, activity, study, work, exercise) |
| pain(noun, trouble, bother, worry, concern) |
| problematic(adjective, tough, severe, grim, painful) |
| refractory(adjective, tough, problematic, trying) |
| responsibility(noun, interest, issue, affair) |
| reverse(noun, trouble, defeat, distress, disturbance) |
| secret(noun, trouble, challenge, question, puzzle) |
| snarl(noun, trouble, difficulty, mess) |
| stew(noun, trouble, defeat, distress, disturbance) |
| struggle(noun, trouble, bother, worry, strain) |
| subject matter(expression, idiom, point, issue, idea) |
| theorem(noun, idea, topic) |
| thesis(noun, point, line, issue, idea) |
| trial(noun, trouble, bother, concern, strain) |
| uncontrollable |
| unruly(adjective, problematic) |
| upset(noun, trouble, bother, defeat, worry) |