noun
mountain of difficult problems; pile of thorny issues
Idiomatic expression describing a situation where many difficult problems have accumulated, like a mountain. Often used in political, business, or organizational contexts.
新内閣は難問山積の状態でスタートした。
The new cabinet started with a mountain of difficult problems.
このプロジェクトは難問山積で、どこから手をつければいいかわからない。
This project is a pile of thorny issues, and I don't know where to start.
A four-character compound (yojijukugo) combining 難問 (difficult problem) and 山積 (pile up like a mountain). The exact origin is uncertain, but it follows a common pattern of metaphorical compounds in Japanese.