from The American Heritage® Dictionary of the English Language, 4th Edition
- transitive v. To improvise and deliver extemporaneously.
- intransitive v. To engage in improvisation, as during delivery of a speech.
- n. Words, music, or actions uttered, performed, or carried out extemporaneously.
- adj. Uttered, performed, or carried out spontaneously. See Synonyms at extemporaneous.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To improvise all or part of a speech or other performance, especially in comedy.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. with little or no preparation or forethought
- adj. said or done without having been planned or written in advance
- v. perform without preparation
- n. remark made spontaneously without prior preparation
From ad lib. (Wiktionary)