Duh means "No shit sherlock" and/or "Thank you captain obvious"

means "Of course you idiot"

A word people use when the obvious is stated.

replacement for the sarcastic retort, " No Kidding! "

Obvious, totally obvious.

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".

Sound used to imitate a mentally retarded person as an answer to an obvious remark or question. The person using "duh" is thereby sarcastically indicating that he/she is not retarded and the forgoing remark or question is obvious to him/her.