The Collaborative International Dictionary
Subnuvolar
Subnuvolar \Sub*nu"vo*lar\, a. [Pref. sub + It. nuvola cloud: cf. L. subnubilus somewhat cloudy.] Under the clouds; attended or partly covered or obscured by clouds; somewhat cloudy. [R. & Poetic]
Subnuvolar lights of evening sharply slant.
--Milnes.
Wiktionary
subnuvolar
a. (context nonce obsolete poetic English) Under the clouds; partly covered or obscured by cloud.