Below is a diagram describe regular and diffuse reflection.
What is the reflection
Regular reflection is one that occurs when light reflects off a smooth surface in a predictable way. The angle of reflection is equal to the angle of incidence, and the reflected rays are all parallel to each other. This is why we can see clear images in mirrors and other smooth surfaces.
Diffuse reflection is known to be one that occurs when light reflects off a rough surface in a more scattered way. The angle of reflection is not always equal to the angle of incidence, and the reflected rays are not all parallel to each other. This is why we see blurry images in rough surfaces like sandpaper or walls.