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1.
Jamaican patios; slang meaning "of course" or "I know"
Q: Yo, you comin' to tha party tonight

A: Yea man, u dun kno!
by Angelene April 22, 2008
 
2.
forsure, agreein wit sumtin.
"dun kno C'sz UP"

"dem bloodsz are bitchesz".."dun kno"
by LocMamii April 08, 2006
 
3.
A verb used in modern London and Caribbean dialects, meaning:

1. You've 'done already known' about something. In other words, you should know, or you do know.

2. An expletive to celebrate something, in the same way you'd say 'get in'.

3. Used incorrectly by many who think it means 'you don't know'.
1. Tempz: It's kicking off right here, dunkno we got the shotgun there! (you should know we've got a shotgun there)

Skepta: Dunkno the myspace (you already know about the myspace)

2. When I score a sick goal on FIFA: Dunkno! Finessed that to shit!
by parrer February 05, 2011
 
4.
1. Like approval or like saying thats wassup

2. Can literally mean: "I don't know." But mostly it is def #1.
1. Amber: Hey Shiela like my new kicks?

Shiela: Dunkno!

2. Billy: Hey bro you coming to the jam tonight?

Bro: Dunkno.
by Pezz123 November 09, 2009
 
5.
to warn someone off and tell them they know bst not to mess with you..
guy1: im sorry i will never say anything rude to u agen

guy2: alieee you fucking know best dunkno!!!
by baddaman3321 December 30, 2009
 
6.
Slurry way of saying "don't know". People either say it like that when they're feeling to lazy to speak properly or don't want to speak at all.
Another reason is because they think it's cool to use slang and miss-pronounce everything.
Example 1

Peter: "Yo comin' to da party ta-night?!"

Jase: " Dun kno mann,think imma be somewhier!"

Example 2

Hailey: "Hey, do you know where I put my keys? I had them just a-"

Carlos: "Dun know..(walks away)"
by nunyobussiness July 27, 2011