This is the 4707th most frequent Russian word.
женщиной
The instrumental case of "женщина," meaning "woman" in English.
In this sentence, "женщиной" is the instrumental case used to describe the woman admired as being strong.
Она восхищалась этой сильной женщиной.
She admired this strong woman.
Here, "женщиной" is mistakenly used instead of "женщине" which is dative case; the correction should be applied in educational context.
Он говорил о доброй женщиной вчера.
He spoke about the kind woman yesterday.
The word "женщиной" is used in instrumental case to describe the grandmother as a remarkable woman.