Gouache (; French: [ɡwaʃ]), body color, or opaque watercolor, is a water-medium paint consisting of natural pigment, water, a binding agent (usually gum arabic or dextrin), and sometimes additional inert material. Gouache is designed to be opaque. Gouache has a considerable history, having been used for at least twelve centuries. It is used most consistently by commercial artists for posters, illustrations, comics, and other design work.
Gouache is similar to watercolor in that it can be re-wetted and dries to a matte finish, and the paint can become infused into its paper support. It is similar to acrylic or oil paints in that it is normally used in an opaque painting style and it can form a superficial layer. Many manufacturers of watercolor paints also produce gouache, and the two can easily be used together. -Gouache - Wikipedia