1. something that one is expected or required to do by moral or legal obligation
2. a tax charged by a government on imported or exported goods
3. the work that a person does as part of their job

Examples

• It is every citizen’s duty to vote in elections.
• The soldier was called to duty overseas.
• Parents have a duty to care for their children.
• The government imposed a duty on imported cars.
• She reported for duty at 6 AM sharp.
• He felt it was his moral duty to help the homeless.
• The customs duty made the foreign goods more expensive.