What verb means to cause to grow thin or weak?

The verb that means to cause to grow thin or weak is "macerate." This term originates from Latin and is commonly used in both culinary and biological contexts. In cooking, to macerate often refers to softening or breaking down food (such as fruit) by soaking it in liquid, which can cause the food to lose its firmness and become 'weaker' in texture. In a biological sense, it can refer to the process of tissue decomposition due to the action of enzymes and fluid, leading to a thinning or weakening of the tissue.

The other choices involve different meanings: "maculate" refers to marking something with spots or stains, "maunder" means to speak in a rambling or incoherent manner, and "ossified" describes something that has become rigid, either physically or in a metaphorical sense, such as thoughts or opinions that have become fixed and unable to change. Therefore, "macerate" is the only verb in this list that directly aligns with the concept of causing something to grow thin or weak.