perfectionist

Concise Oxford English Dictionary © 2008 Oxford University Press:
perfectionism/pəˈfekʃənɪzəm/

▶noun

• 1 refusal to accept any standard short of perfection.

• 2 Philosophy a doctrine holding that religious, moral, social, or political perfection is attainable.

– derivatives
perfectionist noun & adjective,
perfectionistic adjective.