Which of the following words is closest in meaning to “Obdurate”?

Obdurate means stubbornly refusing to change.

• Correct answer - stubborn: it has the same meaning as Obdurate.
• inimitable: impossible to copy - wrong, it does not mean the same as Obdurate.
• ambiguous: having more than one meaning - wrong, it does not mean the same as Obdurate.
• demoralised: having lost confidence - wrong, it does not mean the same as Obdurate.