the mind > mental capacity > knowledge > hiding, concealing from view > keeping from knowledge > [noun] > making obscure > that which conceals or obscures (4)
Of immaterial things. Without of, in more general figurative and metaphorical uses.
transferred and figurative. Anything that obscures or conceals; ‘any state of obscurity or darkness’ (Johnson).
In proverbial, figurative, or allusive uses. Denoting a clouding or obscuring medium or influence. spec. in Espionage, false information to…