Dun simply means "son". Originally started from a handicaped kid in Queens, NY. He couldn't pronounce son, so everytime he said son, it sounded more like dun. Mobb Deep coined the word and still use it today!
Yo! what up dun?
How you living dun?
It is a slang word started out in Queens, NY
particularly the Queens bridge housing projects
It is a distortion of the word "Son" and is used to reference a friend or someone whose name you do not know
ex 1- AYO DUN! WAS HAPPENIN!
ex 2- i want large fries with that dun
Originally used in greeting those who names are unknown to you or have been forgotten, dun has been revolutionized to act as a comma or pause in a sentence, indicating also that the following part is of significance and those around should stop what they are doing if possible and pay close attention. However "DUN" is also used when speaking with close friends and can take on several positions of a sentence.
"Ayo where ya going dun"
"Ayo dun, we bout to go down the road and handle buisnes"
"wassup dun" "safe dun"
Mobb deeps dun language dun means sun
a term used to greet close friends or hated foes
whats good dun you flip them packs.
(translation)hello friend you sell those drugs?