General:
* Dutiful: This is the most direct and common adjective, meaning "characterized by a sense of duty."
* Obligatory: This emphasizes the required nature of the duty.
* Required: Similar to "obligatory," focusing on the necessity of the duty.
* Responsible: This implies a sense of accountability for fulfilling the duty.
Specific:
* Patriotic: Used for duties related to one's country.
* Civic: For duties related to one's community.
* Moral: For duties based on ethical principles.
* Professional: For duties related to one's job or profession.
Figurative:
* Solemn: Can describe a duty that is serious and weighty.
* Sacred: Used for duties considered highly important or inviolable.
The best adjective will depend on the specific meaning you want to convey.