Pursue vs Undefined - What's the difference?

As a verb pursue

is (obsolete|transitive) to follow with harmful intent; to try to harm, to persecute, torment.

lacking a definition or value.

(pursu)

(obsolete) To follow with harmful intent; to try to harm, to persecute, torment.

To follow urgently, originally with intent to capture or harm; to chase.

* Wyclif Bible, John xv. 20

The servant is not greater than his lord. If they have pursued' me, they shall ' pursue you also.

* 2009 , Martin Chulov, ‘Iraqi shoe-thrower claims he suffered torture in jail’, The Guardian , 15 Sep 09:

He now feared for his life, and believed US intelligence agents would pursue him.

To follow, travel down (a particular way, course of action etc.).

Her rival pursued a quite different course.

To aim for, go after (a specified objective, situation etc.).

* 2009 , Benjamin Pogrund, ‘Freeze won't hurt Netanyahu’, The Guardian , 1 Dec 09:

He even stands to gain in world terms: his noisy critics strengthen his projected image of a man determined to pursue peace with Palestinians.

To participate in (an activity, business etc.); to practise, follow (a profession).

(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