This is the 565th most frequent Japanese word.
厚
Thick; deep; kind; cordial.
Here, "厚" in "厚情" is used in a figurative sense to express the depth or extent of someone's kindness.
彼女は厚情で知られています。
She is known for her kindness.
In this sentence, "厚" directly refers to the physical thickness of the ice, emphasizing its extent.
氷が厚すぎて割れない。
The ice is too thick to break.
The word "厚い" is used to describe the physical thickness of an object, in this case, a book cover.