As a Noun: 1. The process or result of trying to guess something without knowing all the facts. English = guesswork, speculation. As a Verb or Adjective: 1. To behave in a foolish, strange or childish way. English = (be) crazy, (be) silly. 2. To lack good judgement or intelligence and to be not at all sensible. English = (be) stupid. 3. To try to guess something without knowing all the facts. English = guess, speculate.