あかん

bad; impossible; hopeless; no; cannot

Word type: 

Standard: 

だめ

Standard kanji: 

駄目

Example: 

そんなことしたらあかん
Don't do that!

A: テストどうやった?
B: あかんかってん。

A : How was the test?
B: It was no good.

あかん、また、ねぼうしてもうた。
Agh! I overslept again.

週末も仕事せなあかんねん。
I have to work during weekends.

Commentary: 

"あかん" is one of the most recognizable Kansai words. One of the the reasons for its ubiquity are its many uses. See examples above.

あかん can also be used in certain verb constructions, for example:

週末も仕事せなあかんねん。
I have to work during weekends.

See the grammar page for せなあかん for more information.