Which word means to make something extremely thin?

The term that means to make something extremely thin is "emaciate." This word specifically refers to the process of becoming abnormally thin or weak, typically due to a lack of nutrition or severe illness. In a broader sense, it emphasizes more than just a reduction in thickness; it conveys a significant and often concerning level of thinness that affects health and wellness.

While "thin out" does suggest reducing thickness, it is more commonly used in contexts like thinning out a crowd or a forest rather than specifically indicating an extreme level of thinness. "Reduce" and "minimize," though related to making something smaller or lesser in degree, lack the connotation of extreme thinness that "emaciate" carries. Therefore, "emaciate" is the most precise term when referring to making something extremely thin.