Miss Darcy and her brother appeared, and this formidable introduction took place.
Such formidable accounts of her ladyship, and her manner of living, quite frightened Maria Lucas who had been little used to company, and she looked forward to her introduction at Rosings with as much apprehension as her father had done to his presentation at St. James’s.
He owed a good deal in town, but his debts of honour were still more formidable.
She was not rendered formidable by silence; but whatever she said was spoken in so authoritative a tone, as marked her self-importance, and brought Mr. Wickham immediately to Elizabeth’s mind; and from the observation of the day altogether, she believed Lady Catherine to be exactly what he represented.
There are no more uses of "formidable" in the book.