The Collaborative International Dictionary of English v.0.48:

Obnubilate \Ob*nu"bi*late\, v. t. [L. obnubilatus, p. p. of
   obnubilare to obscure. See Ob-, and Nubilate.]
   To cloud; to obscure. [Obs.] --Burton. -- Ob*nu"bi*la"tion,
   n. [Obs.] --Beddoes.
   [1913 Webster]

WordNet (r) 3.0 (2006):

obnubilate
    v 1: make less visible or unclear; "The stars are obscured by
         the clouds"; "the big elm tree obscures our view of the
         valley" [syn: obscure, befog, becloud, obnubilate,
         haze over, fog, cloud, mist]
    2: make unclear, indistinct, or blurred; "Her remarks confused
       the debate"; "Their words obnubilate their intentions" [syn:
       confuse, blur, obscure, obnubilate]