Question

if we cannot see through an object at all , it is an _ object

Answer 1

Opaque object is your answer

Answer 2

If we cannot see through an object at all its an Opaque object because Opaque object does not allow the passes of light through it.
Example- table,book and human beings means you yourself.
There are two more types of objects - 1) transparent object- an object which allows the complete passage of light.
Example- glass , clean water etc.
2) translucent object- an object which allows the partial passage of light is called translucent object.
Example- butter glass, oil paper etc.
Anyway according to your question, if we cannot se through an object at all, it's opaque object.
Hope it helps!
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