Used as the word "dun", meaning a greeting for someone particularly male. Originated from a speech impedimate of the word "son". Spoken and pronuced with a lisp or hard New York accent.

v. collectively or individually finding someone/something to blame for a problem, as opposed to brainstorming which connotes finding solutions to a problem

n. the act of finding someone/something to blame for a problem

(from a TV ad for HD television)