extemporize Get Printable Handwriting (ex-tem-po-rize) 4 syllables Learn It! Spelling Test Definition verb. 1 to speak without preparation or reference to notes; 2.in music to compose as one performs; improvise. Example Sentence He can extemporize on any of a number of subjects. Synonyms ad-lib; play it by ear; off the cuff Antonyms prepared; planned Share with your friends: