• 難むずかしい — difficult
• 困難こんなん — hardship / difficulty
• 災難さいなん — disaster / misfortune
• 避難ひなん — evacuation / refuge
• 遭難そうなん — shipwreck / accident
• 難民なんみん — refugee

難 combines the 隹 (bird) radical with phonetic and semantic elements suggesting hardship or complexity. Historically, it related to the difficulty of catching birds, and later broadened to mean trouble, crisis, and disaster.

この問題もんだいは とても難むずかしいです。
This problem is very difficult.

災難さいなんが 続つづいている。
Disasters keep occurring.