Hidden, out of sight or inconspicuous.
Dark, faint or indistinct.
Difficult to understand.
Not well-known.
Unknown or uncertain; unclear.
To hide, put out of sight etc.
To render obscure; to darken; to make dim; to keep in the dark; to hide; to make less visible, intelligible, legible, glorious, beautiful, or illustrious.
out of focus; blurry.
dulled or intentionally blunt.
To sharpen (an image) by creating a blurred ("unsharp") negative as a mask, and then combining that mask with the original.