transitive. To free from shadow or shade.

(un-, prefix2 affix 1b(b).)

transitive. To give a definite border or outline to (a visible object); to render distinct, define. Now rare.

transitive. To restore (a design, etc.) to clearness or freshness; to bring out clearly.

transitive. To make distinct.

transitive. To make (a blurred image) sharper; to cancel the effect of blurring on (an image).