Synonyms of spur-of-the-moment

1 Syllable
free, snap, fake
2 Syllables
made-up, adlib, jamming, casual, bandaid, improv, band-aid, offhand, ad-lib
3 Syllables
on-the-spot, spontaneous, unstudied, expedient, unscripted, makeshift, impromptu, unplanned, informal, impetuous, off-the-cuff
4 Syllables
improviso, improvised, unprepared, unrehearsed, immediate, automatic, extempore
5 Syllables
extemporaneous, autoschediastic, extemporary
6 Syllables
unpremeditated, improvisatory