| English | eng-000 |
| difficult problem | |
| বাংলা | ben-000 | প্যাঁচ |
| 普通话 | cmn-000 | 难题 |
| 國語 | cmn-001 | 疑難雜症 |
| 國語 | cmn-001 | 難題 |
| Deutsch | deu-000 | schwierige Aufgabe |
| Deutsch | deu-000 | schwierige Frage |
| Deutsch | deu-000 | schwieriges Problem |
| English | eng-000 | challenge |
| English | eng-000 | crux |
| English | eng-000 | difficult question |
| English | eng-000 | difficulty |
| English | eng-000 | false position |
| English | eng-000 | nut |
| English | eng-000 | perplexity |
| English | eng-000 | puzzling thing |
| English | eng-000 | quandary |
| English | eng-000 | serious problem |
| français | fra-000 | colle |
| français | fra-000 | sujet difficile |
| 日本語 | jpn-000 | 難問 |
| 日本語 | jpn-000 | 難題 |
| にほんご | jpn-002 | なんもん |
| Tâi-gí | nan-003 | gĭ-lăn cha̍p-chèng |
| Tâi-gí | nan-003 | lăn-tĕ |
| русский | rus-000 | серьезная проблема |
| русский | rus-000 | сложный задача |
| தமிழ் | tam-000 | விஷமக்கணக்கு |
| ภาษาไทย | tha-000 | ปัญหายุ่งยาก |