1. 模糊；不透明
Opacity is the quality of being difficult to see through.

2. 费解；难懂；晦涩
If you refer to something's opacity, you mean that it is difficult to understand.

1. the quality of being opaque to a degree
the degree to which something reduces the passage of light

Synonym: opaqueness

2. incomprehensibility resulting from obscurity of meaning

Synonym: opaqueness

3. the phenomenon of not permitting the passage of electromagnetic radiation