As a Noun: 1. A formal promise, especially a promise to tell the truth in court often made by swearing on a Bible. English = oath. 2. Your status as a person who legally belongs to a particular country. English = citizenship. As a Verb or Adjective: 1. To make a formal promise, especially a promise to tell the truth in court by swearing on a Bible. English = swear an oath, swear. 2. To take part in a formal ceremony in which you legally become a citizen of a country.