無理xだめ
hi, i was wondering whats the difference between 無理 a だめ and when to use them...

both should mean that something is not posible.. and why do you use 無理しないで。when saying ,,Don't overwork yourself.,,?

Question

無理xだめ
hi, i was wondering whats the difference between 無理 a だめ and when to use them...

both should mean that something is not posible.. and why do you use 無理しないで。when saying ,,Don't overwork yourself.,,?

Answer

I looked them up in a Japanese dictionary. Here are some of their meanings.

無理
1. irrational, 2. impossible, 3. overdone

駄目
1. useless, 2. ineffective, 3. impossible, 4. forbidden

As you say, both of the two words have a meaning of impossible. In this case, they should be interchangeable (there may be a difference in their nuances, though).

Regarding 無理しないで, this would be associated with 3 in the above.

The following URL is the Japanese dictionary, where you can see some examples.
https://kotobank.jp/word/%E7%84%A1%E7%90%86-642522#E3.83.87.E3.82.B8.E3.82.BF.E3.83.AB.E5.A4.A7.E8.BE.9E.E6.B3.89