unyielding

adjective
1
if a person is unyielding, they are not easily influenced and they are unlikely to change their mind
سرسخت, انعطاف‌ناپذیر, غیرقابل‌انعطاف
synonym inflexible
2
an unyielding substance or object does not bend or break when pressure is put on it
محکم, سفت, سخت, مقاوم, صلب