As a Noun: 1. Physical or mental work which is difficult and very hard, even painful. English = labour, toil, exertion. Formal English = travail. 2. An action or job that requires an unusual amount of physical or mental energy to do it. English = effort. As a Verb or Adjective: 1. To work hard or a lot, to make an effort. 2. Of an action or job, to require or take a lot of effort to do. English = (be) laborious. 3. Of a person, to be working hard or concentrating on a task, so that you are not free to do anything else. English = (be) busy.