"Muscosity" Natural Recordings by Native Speakers
The word "viscosity" (not "muscosity") refers to the thickness or fluidity of a liquid. It is a measure of how resistant a fluid is to flow. In other words, it is a measure of how thick or thin a liquid is.
Having a lot of muscle, or relating to muscles. Strong, powerful, and well-developed in shape and size.
To muscularize means to make something or someone physically stronger or more robust, especially through exercise or training. It can also mean to increase the size or prominence of something, such as muscles, by adding more tissue or structure.