shelters is a form of:

Opacity



noun
1.
(state or quality of being opaque, impermeability, density, imperiousness, obscurity) ភាពបាំងបាត់
ENGLISH MEANING
noun
1.
The state of being opaque; the quality of a body which renders it impervious to the rays of light; want of transparency; opaqueness.
2.
Obscurity; want of clearness.