noun
Refers to the quality of being opaque, either physically (not allowing light to pass through) or figuratively (lack of transparency in processes or communication).
このガラスの不透明性は高い。
The opacity of this glass is high.
政府の不透明性が批判されている。
The opacity of the government is being criticized.
Compound of 不 (fu, 'not') + 透明 (tōmei, 'transparent') + 性 (sei, '-ness, -ity'), literally 'non-transparency-ness'.