50 entries under unprepared topic. ×

5
undevised(adjective, unplanned, unintentional, accidental)
4
automatic(adjective, simple, passionate, violent, natural)
4
improviso(adjective, free, casual, spontaneous)
4
rough-and-ready
3
by ear(expression, adjective, idiom, free, casual)
3
extemporized(adjective, fake, informal, spontaneous)
3
fake(adjective, free, casual, impulsive, spontaneous)
3
immediate(noun, adjective, free, casual, impulsive)
3
improvisatory(adjective, free, casual, impulsive, impulse)
3
unarranged(adjective, spontaneous, unplanned, unrehearsed)
3
unscripted(adjective, fake, spontaneous, impromptu)
2
expedient(adjective, free, casual, impulsive, spontaneous)
2
ill-considered(adjective, impulsive)
1
autoschediastic(adjective, free, casual, impulsive, spontaneous)
1
dashed off(expression, fake, unplanned, unrehearsed)
1
faked(fake, unplanned, unrehearsed, unscripted)
1
free(adjective, simple, natural, casual, impulsive)
1
improv(adjective, free, fake, casual, spontaneous)
1
jamming(adjective, free, casual, impulsive, spontaneous)
1
on-the-spot(adjective, free, casual, impulsive, spontaneous)
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APASmart Define. (2015). extemporaneous thesaurus. Retrieved October 2, 2026, from https://smartdefine.org/extemporaneous/thesaurus/synonyms
ChicagoSmart Define. 2015. "extemporaneous thesaurus" https://smartdefine.org/extemporaneous/thesaurus/synonyms (accessed October 2, 2026).
HarvardSmart Define 2015, extemporaneous thesaurus, Smart Define, viewed 2 October, 2026, <https://smartdefine.org/extemporaneous/thesaurus/synonyms>.
MLASmart Define. "extemporaneous thesaurus" 13 April 2015. Web. 2 October 2026. <https://smartdefine.org/extemporaneous/thesaurus/synonyms>