Caliginous

Ca*lig"i*nous (?), a. [L. caliginosus; cf. F. caligineux.] Affected with darkness or dimness; dark; obscure. [R.] Blount.

The caliginous regions of the air.
Hallywell.

-- Ca*lig"i*nous*ly, adv. -- Ca*lig"i*nous*ness, n.