Question about using だめ です


A student asks "じしょ を つかって も いい です か？"

Teacher replies" いいえ だめ です"

I want to know, if possible, how could he have used だめ です to say the full
sentence of "no, you cannot use the dictionary" or is だめ です equivalent to
english "no you can't"?




The full sentence would be いいえ、辞書{じしょ}を使{つか}っては駄目{だめ}です, literally translating
'No, you cannot use the dictionary. You could also say いけません or なりません in place
of 駄目{だめ}; all three can also be used in plain form, as 駄目{だめ}だ, いけない, and
ならない.




English translation is not the literal meaning. だめ is not _can't_. It means
'no good'. So the teacher is basically saying **"No, (using a dictionary is)
no good."**  
  
It's weird to say that kind of sentence in English so we use the context and
create a more natural translation, which is **'No you can't (use a
dictionary)."**

