最重要

most important, of utmost importance

最 most; utmost (superlative) + 重要 important
noun Rare #41,508
most important, of utmost importance Often used before a noun to mean “most important” or “top-priority.”
JA: これは最重要問題です。
EN: This is the most important issue.

これは最重要問題だ。

This is the most important issue.