thickly covered

Your trousers are coated in mud! 你的裤子上满是泥巴！

If your tongue is coated, it is covered with a layer of a greyish-white substance, often because you are ill.

with a covering of the stated substance

sugar-coated almonds 糖衣杏仁

(of an animal) with a coat (= hair, wool, or fur) of the stated type

a smooth-coated dog 皮毛光滑的狗