Obscure
Part of speech: verb
Definition: To darken, make faint etc. To hide, put out of sight etc.
Part of speech: adjective
Definition: Dark, faint or indistinct. Hidden, out of sight or inconspicuous, Difficult to understand.
Example sentence: Intellectual comradeship requires that you think your thoughts through to the place where you can make the complex seem simple, the obscure quite clear.
Invisible
Part of speech: adjective
Definition: Not able to be seen; not visible.
Example sentence: Setting goals is the first step in turning the invisible into the visible.