Blunder vs Undefined - What's the difference?

As a noun blunder

is a clumsy or embarrassing mistake.

is to make a clumsy or stupid mistake.

lacking a definition or value.

(wikipedia blunder)

(en noun)

A clumsy or embarrassing mistake.

* (error) blooper, boo-boo, error, faux pas, fluff, flub, fumble, gaffe, goof, lapse, mistake, slip, stumble, thinko

(en verb)

To make a clumsy or stupid mistake.

to blunder in preparing a medical prescription

To move blindly or clumsily.

* Goldsmith

I was never distinguished for address, and have often even blundered in making my bow.

* Dryden

blunders on, and staggers every pace

To cause to make a mistake.

* Ditton

To blunder an adversary.

To do or treat in a blundering manner; to confuse.

* Stillingfleet

He blunders and confounds all these together.

* ----

(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