Myriamn, it seems you still have a problem using Arabic dictionaries. If this is the case, I strongly suggest you use modern dictionaries where you look up the word as they are written not through their roots. So if you look up متعنت in an Arabic-English translation, you'll get its translation (e.g. here) and if you look it up in an Arabic-Arabic dictionary you'll get its definition, sometimes with its root (like here where the root is given in definition #2 [ع-ن-ت]).
Also, please don't forget to provide context, and search thoroughly for the answer before opening a thread.
Who told you that متعنّت means stubborn? In some contexts it can be used to mean stubborn but the general meaning is "difficult", from the root ع ن ت that has the main meaning of creating difficulty.
There are a number of meanings in English to this word that much closer to its meaning than stubborn, I would go for onerous, uncooperative, adamant, or demanding. Of course, the word does imply that the person is being difficult deliberately otherwise one would just use صعب.
by the way, for stubborn I would use عنيد rather than any of the options above as this is the most common word for stubborn in Arabic.
التعنت is much stronger than العناد in my openion, plus it has other connotations. Why not just use عنيد. In your case this would be لا تكن عنيداً and on the streets you could always say ما تعنّد or ما تكون عنيد.