extempore
ex-tem-po-re
adjective
Done or spoken without any prior preparation or rehearsal.
"He delivered an extempore speech."
adverb
Performed or spoken spontaneously, without prior planning.
"She spoke extempore at the meeting."
Thesaurus
Synonyms: impromptu, offhanded, unprepared, unrehearsed, extemporaneous, offhand, ad-lib, off-the-cuff, extemporary, extemporarily, extemporaneously