As a Noun: 1. A story or idea which is made up and not true. Its purpose is often dishonest. It is like a lie but it is not as bad or as serious. English = invention, concoction, contrivance. 2. A situation or event that you think about or imagine, although it is unlikely to happen or be true. English = fantasy, make believe. 3. A story or stories about imaginary people and events, especially when written down in books. English = fiction. 4. The process or result of trying to guess something without knowing all the facts. English = guesswork, speculation. As a Verb or Adjective: 1. To make up an idea or story which is not true, often for dishonest reasons. English = make up, invent, concoct, contrive. 2. To think imaginatively about something for creative pleasure or because you would like it to happen even though it is unlikely to happen. English = fantasise, make believe. 3. To make up a story, based on something that actually happened, but with some details changed or added. English = fictionalise. 4. To say something in a play or speech which has not been planned or prepared beforehand; to give an answer when you do not know if it is correct. English = ad lib; guess.