Top Definition The sound between scenes in Law and Order. The
expression originated when 4chan changed the "Post Successful"
page and font to look like the Law and Order black screen
between scenes. The page played the sound, "Dun Dun," from Law
and Order. 4chan /b/tards began to post the expression, "Dun
Dun," anywhere to import a sense of finality or just randomly.
Tits or gtfo. Dun dun. от Transmigraine 25 май 2010 When a
person can't get himself to talk about a certain ongoing subject
(normally on chatrooms) and is put in a awkward situation, where
some might expect a reaction from him and he goes,  "dun dun."
It comes from "so done with this". Usually related with Otaku
culture for some reason. Person 1: I just raped this bitch so
fucking good, i swear i did.  Person 2: Hahaha so funny!  Person
3. o.o.. dun dun от TheWanAndOnly 19 декември 2013 someone who
dun-dun dem all dey call her dun-dun...dun-dun em all!!! от Rae
Nicole 28 май 2008 ur people. ur ace Chill out dun dun от
DatKiDD 05 декември 2003 A