Synonyms of unrehearsed

2 Syllables
bandaid, band-aid, ad-lib
3 Syllables
adlibbed, ad-libbing, impromptu, off-the-cuff
4 Syllables
unpracticed, improvised, unprepared, impulsive
5 Syllables
spur-of-the-moment, extemporaneous, autoschediastic, extemporary
6 Syllables
improvisatory