Another erudite vocable.

ca·lig·i·nous /kəˈlɪdʒənəs/

–adjective Archaic.
misty; dim; dark.

[Origin: 1540–50; < L cālīginōsus misty, equiv. to cālīgin– (s. of cālīgō) mist + –ōsus -ous]

—Related forms
ca·lig·i·nos·i·ty, ca·lig·i·nous·ness, noun
ca·lig·i·nous·ly, adverb

Source: Dictionary.com.