| mess(noun, trouble, fix, worry, difficulty) |
| nut |
| paradox(noun, trouble, challenge, secret, puzzle) |
| puzzlement(noun, trouble, challenge, question, secret) |
| topic(noun, trouble, worry, concern, point) |
| concern(noun, trouble, worry, strain, point) |
| fix(noun, difficulty, mess, embarrassment, bug) |
| headache(noun, trouble, concern, strain, difficulty) |
| jam(noun, fix, check, delay, stay) |
| knot(noun, difficulty, puzzle, mystery, riddle) |
| moot point(expression, idiom, idea, inquiry) |
| puzzler(noun, difficulty, challenge, question, disadvantage) |
| text(noun, point, line, issue, idea) |
| theme(noun, activity, study, work, point) |
| why(noun, trouble, challenge, question, secret) |
| impediment(noun, trouble, check, delay, stay) |
| affair(noun, trouble, worry, concern, point) |
| bug(noun, difficulty, weakness, fault, failing) |
| bugaboo(noun, worry, concern, challenge, question) |
| bugbear(noun, worry, concern, ghost) |