Blacken vs Undefined - What's the difference?

As a verb blacken

is to make black.

lacking a definition or value.

(en verb)

To make black.

To make dirty.

To defame or sully.

Malice delights to blacken the characters of prominent men. — Napoleon Bonaparte

To cook (meat or fish) by coating with pepper, etc., and quickly searing in a hot pan.

To become black.

The sky blackened as the storm clouds rolled in.

* (make black ): black, denigrate * (make dirty ): dirty, soil * (defame ): defame, denigrate, sully, taint, tarnish

(wikipedia undefined) (-)

Lacking a definition or value.

(mathematics, computing) That does not have a meaning and is thus not assigned an interpretation.

The result of division by zero is undefined .

* defined