The antonyms for the word "most waferthin" can be thick, chunky, substantial, sturdy, and stout. These words are used to describe objects that are not thin, delicate, or fragile. For instance, a thick layer of cake icing, a chunky and substantial block of cheese, a sturdy yet stylish piece of furniture, and a stout branch of a tree can be considered as antonyms of something that is waferthin. Depending on the context, the use of antonyms can help to create contrast or emphasize the differences between two objects or situations.