But would these not make her an even more formidable tool for the Harkonnens?
We will woo the formidable Thufir Hawat.
One of the most formidable Mentats in all history, a Mentat trained to kill, and they’ll toss him to me like some silly toy to be broken.
If you had finesse and subtlety to match such courage, you’d be truly formidable.
By the time of Shaddam IV, while they were still formidable, their strength had been sapped by overconfidence, and the sustaining mystique of their warrior religion had been deeply undermined by cynicism.
Formidable indeed," the Duke murmured, and Paul saw the proud smile on his father’s face.
There are no more uses of "formidable" in the book.