Pronunciation: (ik-stem"pu-rā'nē-us), [key]
1. done, spoken, performed, etc., without special advance preparation; impromptu: an extemporaneous speech.
2. previously planned but delivered with the help of few or no notes: extemporaneous lectures.
3. speaking or performing with little or no advance preparation: extemporaneous actors.
4. made for the occasion, as a shelter.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.