As a Noun: 1. A situation in which a lot of things are happening or being done. English = activity. 2. Something that you spend time doing. English = activity. 3. The things that a group does in order to achieve their aims, especially as part of a learning exercise. English = activity. 4. Something done for a particular purpose, or on a particular occasion. English = action. As a Verb or Adjective: 1. Of a person or animal, to be energetic and always busy or moving about. English = (be) active.