tough 同stubborn有甚麼分別?

tough-强硬
e.g. he is a tough man and never be defeated.
stubborn-頑固
e.g. he is so stubborn that never seek advise.

Actually it depends on what you are trying to say.
The word tough does not necessarily need to be a negative word but stubborn is definitely negative. Take a look at the first answer you get, the word tough can be sort of positive in saying a guy is persistent and not giving up but stubborn people won't change their minds easily.

It really depends on how you use the words but personally, I think the word stubborn 語氣較重.

stubborn是頑固的 比較禮貌
tough是惡棍 語氣較重