Opaque.
The word for materials that do not allow light to pass through is "opaque." This means that the material is not transparent or translucent, resulting in the obstruction of light passing through it.
The word you're looking for is "transparent." Objects that are transparent allow light to pass through them without scattering the light.
The word you're looking for is opaque.
Transparent materials.
Transparent materials allow light to freely pass through them. Translucent materials also allow light to pass through them, but change the colour of the light.
Transparency.
The word you're looking for is "transparent." This term describes a substance that allows light to pass through without significant distortion or absorption.
Opaque is the term used to describe an object or substance that stops all light passing.
The word is translucent. It refers to a material that allows some light to pass through, but diffuses it in the process, making objects on the other side appear blurry or unclear.
The word you're looking for is "selective." It means allowing certain things to pass through while blocking others.
You would say that the wood is opaque.
Transparent materials will always allow light to pass through, translucent materials will allow light to pass through as well but the light rays will be scattered. Opaque materials will not allow any light to pass through.