This is the 9227th most frequent Japanese word.
甚大
"甚大" means "immense" or "extremely large."
The word '甚大' is used as an adjective to describe the significant extent or severity of the damage suffered.
甚大な被害を受けました。
We suffered significant damage.
Here, '甚大' modifies '努力' to emphasize the considerable magnitude of effort needed.
甚大的な努力が必要です。
Significant efforts are required.
In this sentence, '甚大' characterizes '貢献' to highlight the importance and substantial impact of his contributions.