Opaque materials are materials that light cannot pass through them. They do not cause reflection when rays of light fall on their surfaces. Instead, the light scatters in a very negligible volume by the interior of the opaque materials. Although opaque materials can also diffuse the light in a small volume, translucent materials are known to have this feature (scattering).
In other words, translucent materials produce broader scattering compared to opaque materials. Translucent materials are materials that allow some light to pass through them. They are not considered transparent objects because they diffuse the light. On the contrary, opaque materials don't allow the light to pass through them.
Examples of opaque materials are plastics, ceramic, stone, wood, etc. One of the common features of opaque materials is that they form shadows. However, some materials allow light to pass through them. They are known as transparent materials. Examples of transparent materials are water, clear glass, air, etc.