As a Noun: 1. The ability to easily and clearly show people how you think and feel by using your body and language. English = expressiveness. As a Verb or Adjective: 1. To have the ability to easily and clearly show people how you think and feel by using your body and language. English = (be) expressive. 2. To show people how you think and feel by using your body and language. English = express oneself. 3. To get rid of any fear of letting other people know how you think and feel about something. Idiomatic English = let oneself go, let it all out, let go.