duty
work that you are obliged to perform for moral or legal reasons
the duties of the job
responsibility
obligation
the social force that binds you to the courses of action demanded by that force
we must instill a sense of duty in our children
every right implies a responsibility; every opportunity, an obligation; every possession, a duty
John D.Rockefeller Jr
tariff
a government tax on imports or exports
they signed a treaty to lower duties on trade between their countries