The phrase "stubborn enemy" is correct and usable in written English.
It can be used to describe an adversary who is unyielding or resistant to change.
Example: "Despite our best efforts to negotiate peace, we found ourselves facing a stubborn enemy unwilling to compromise."
Alternatives: "unyielding foe" or "obstinate adversary."
He dresses all in black, which makes him look like a fascist torturer in a political thriller, trying to elicit the truth from a stubborn enemy spy.
First, Roosevelt, at Casablanca, decided that America would pursue a policy of "unconditional surrender" against Germany and Japan — a declaration, Carroll writes, of "a readiness to embark, if a stubborn enemy so invited it, on a program of total destruction".
We are dealing here with a tenacious and stubborn enemy.
This catastrophe left Rome completely uncovered; but Hannibal, having resolved not to attack the capital before he could collect a more overwhelming force, directed his march toward the south of Italy, where he hoped to stir up the peoples who had formerly been the most stubborn enemies of Rome.
The losses, and frustration at the continuing stubborn resistance by the enemy after an entry into the capital greeted with celebration by residents, has led to something approaching fury among some of the revolutionaries in the last few days.
Mostly German refugees trained in psychological warfare, they tried to break down the enemy's often stubborn resistance to the facts and encouraged surrender.
This is not the first time that such rumours have gone round: Mr Hayami's stubborn independence has made him enemies in government.
But in the case of Mr. Mack, who for Ms. Cruz has been a mentor, champion as well as her most stubborn defender against her many enemies, the decision to force her retirement was undoubtedly wrenching.
With an actual enemy to fight, his stubborn optimism resurfaced until surgery revealed that his cancer had metastasized.
The battleship continued her firing runs in spite of shell geysers blossoming about her and difficulty spotting the targets because of smoke; however, the enemy gunners were just as stubborn and skilled.
Although the Jews have suffered more than most, the stubborn refusal to celebrate the demise of our enemies, or any military triumph, has been the hallmark of Jewish history.
