猛毒の「猛」ですが、「very」とか「highly」で大丈夫ですよ。
例文:
- In Japan, the highly poisonous Puffer Fish is a delicacy enjoyed at sushi bars across the country.
死ぬほどの毒でしたら「Fatally poisonous」と言います。
例文:
- There is a frog in the Amazon that is known for being fatally poisonous.