entirely useless; completely worthless
Emphatic reduplication of 駄目 (no good), meaning hopelessly bad or beyond repair. Often used in casual, colloquial contexts.
See also: だめ
This computer is completely useless now.
no no!; don't!
Used as an interjection to strongly forbid or reject something, often in a playful or emphatic tone. Equivalent to repeating 駄目 for emphasis.
See also: だめ
No, no, don't do that!
His driving is totally hopeless; I'm too scared to ride with him.
ダメダメ、まだ食べちゃダメ！
No, no, you can't eat it yet!
Kanji spelling exists but is very rare; the word is usually written in kana.
Reduplication of 駄目 (だめ, 'no good') for emphasis. The exact origin of 駄目 is uncertain, but it is often associated with the game of Go, where 駄目 refers to a useless move.