opacity

1. N-UNCOUNT Opacity is the quality of being difficult to see through. 不透明性[正式]

Opacity of the eye lens can be induced by deficiency of certain vitamins. 眼球晶状体的混浊可由缺乏某些维生素引起。

2. N-UNCOUNT If you refer to something's opacity, you mean that it is difficult to understand. 晦涩难懂[正式]

...a stupefying verbal opacity. ... 让人惊讶的晦涩难懂的语言。