A very serious problem or major issue; widely used in everyday speech and news to indicate something of great concern.
その不祥事は会社にとって大問題になった。
The scandal became a major problem for the company.
彼の遅刻は些細だが、品質の低下は大問題だ。
His tardiness is minor, but the drop in quality is a big problem.
このままでは環境汚染が大問題に発展する可能性がある。
At this rate, environmental pollution could develop into a major issue.