That was not the phrase for such a girl as Miss Tulliver; it would have been more correct to say that she had been actuated by mere unwomanly boldness and unbridled passion.
There are no more uses of "unbridled" in the book.
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Wolves are also strict monogamists, and although I do not necessarily consider this an admirable trait, it does make the reputation for unbridled promiscuity which we have bestowed on the wolf somewhat hypocritical.
Farley Mowat -- Never Cry Wolf
It was attached to his saddle, which was cinched around his horse, which, when they stopped, could be subtly unbridled, just enough so that with a fierce tug from her end, the chain would rip the saddle off the beast, he’d tumble to the ground, and she would— She sensed Captain Westfall’s attention.