Define Jack All Meaning

Absolutely nothing. syn: jack shit.

A person of many characters and / or personalities. A very exciting person who will always keep you guessing and on your toes. You will never know if the person is coming or going often leaving you in a redundant tail spin guessing game of Name that Character!
"How exciting.. who is Cynthia Daniele today!? A minister!?"
"Nope, guess again!"
"A Sunday school teacher!?" "Jay Leno because of your huge chin!?"
"No asshole! I am a sailor because I swear like one!"
"Mrs. Daniele, please refrain from diarreah of the mouth. Especially in front of the children. Who raised you.. a pack of wolves? Clean up your act because your kind is certainly not welcome here."
"You're a bunch of bitches.. ha!"
*children crying*
"Oh, they just need a good ass whooping! F**kers!"
*Mrs. Daniele escorted out*

The other definitions are wrong.
A Jack of all Trades is someone who is decent at everything, but not especially adept at any one thing.

A man who has mastered all ways of masturbation. Also has the ability to masturbate anywhere at anytime, at will without remorse.

A person who is skilled at a variety of different things, but not to the same level as a person who is specialised in one of these things.

a person who is good at many things but has no particular specialty (often with master of none at the end)

A term used to describe someone who knows a lot about many things, but, with the second tag "master of none" added it transforms into a derogatory phrase meant to emphasize how mastery of one skill is important for deeper knowledge.

However, one, oft forgotten tag is the third one: "is oftentimes better than a master of one". Instantly, the term reverses meaning, symbolizing how a person who knows a lot about many things that integrates their skills allows them to surpass even a master of one.

Interesting phrase, nonetheless.

A person who has the ability to piss off anyone at any time, and anywhere. Typically, these people are unpleasant to be around due to the sheer amount of ignorance they emit, or lack of caring while being an asshole. They never fail to make someone's day more unpleasant than what it would, or not, have been. Atop of this, they also seem to be capable of this in more than one way and rather effortlessly, hence the name "Jack of All Asses.".

The ultimate Jackass. Everyone knows at least one of these. Will gladly accept credit for others accomplishments, usually full of themselves for no reason, and tend to have exceptional manipulative skills. Can often be seen reading poetry at Starbucks.

A politically correct way of describing someone with multiple personality disorder