'Frightening' in the Bible

Their rims were large and frightening. Each of their four rims were full of eyes all around.

“While I was watching in the night visions, a fourth beast appeared, frightening and dreadful, and incredibly strong, with large iron teeth. It devoured and crushed, and it trampled with its feet whatever was left. It was different from all the beasts before it, and it had 10 horns.