Synonyms of extemporaneous

1 Syllable
free, snap, fake
2 Syllables
made-up, adlib, jamming, casual, unmeant, bandaid, improv, band-aid, offhand, ad-lib
3 Syllables
on-the-spot, spontaneous, unstudied, expedient, unscripted, makeshift, unbidden, adlibbed, ad-libbing, impromptu, unplanned, informal, hot-and-cold, unprompted
4 Syllables
improviso, improvised, unintended, unprepared, unrehearsed, impulsive, immediate, automatic, extempore, undesigned, rough-and-ready, wild-and-woolly
5 Syllables
spur-of-the-moment, unpremediated, unintentional, unmeditated, autoschediastic, extemporary
6 Syllables
unpremeditated, improvisatory