1. Of glass, to be difficult to see through because it is not clear or clean.
2. To be difficult to see through the air or to see something in the distance because the air is full of dust, haze or mist. English = (be) hazy, (be) obscure, (be) unclear.
3. Of an idea, to be difficult to think about easily because it is not precise or exact enough. English = (be) vague.