A word people use when the obvious is stated.

A basic unit of measurement of human stupidity. One "duh" is a single unit of stupidity, for example, misplacing your keys would be approximately one duh. Due to the large amounts of stupidity present in the world, more practical units are megaduhs(10^6) or gigaduhs(10^9). Still larger units such as exaduhs(10^18) or yottaduhs(10^24) are more appropriate for measuring stupidity on a global level.

Originally an insult. It is the sound that a mentally handicapped person makes. In the beginning, the word was complete with a hand gesture of smacking your wrist across your chest. Means "obviously".

The sound a retard makes.

1. Used to indicate that something is so obvious that even a retard could figure it out.

2. Shorthand for, “How did I not think of that? I am such an idiot!”

Obvious, totally obvious.

The word Duh is also used to show an evidence. Something that someone is stupid to not know.It is more used in french. Here is an exemple:

it means obviously... like, when someone says something you know already, something evident... --often used sarcastically--