extemporise
ex·tem·po·rise
verb
1.
perform without preparation
- “he extemporized a speech at the wedding”
Phrases
- off the cuff
- off the top of one's head
Related words
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.