63 entries under spontaneous topic. ×

27
offhand(adjective, adverb, free, simple, fake)
27
unprepared(adjective, adverb, free, ready)
24
extemporaneous(adjective, adverb, simple, informal, natural)
24
extempore(adjective, adverb, free, simple, fake)
17
unrehearsed(adjective, free, impulsive, prepared)
16
extemporary(adjective, free, casual, impulsive, prepared)
16
improvised(adjective, free, simple, fake, informal)
14
unpremeditated(adjective, adverb, free, impulsive, planned)
14
unplanned(adjective, free, simple, fake, informal)
13
ad-lib(noun, adjective, adverb, free, simple)
12
makeshift(adjective, adverb, free, unprepared)
12
off-the-cuff(adjective, adverb, simple, informal, natural)
11
casual(adjective, free, simple, fake, natural)
10
instinctive(adjective, simple, natural, casual, impulsive)
10
spur-of-the-moment(adjective, adverb, free, prepared)
9
unstudied(adjective, adverb, free, simple, fake)
9
improviso(adjective, adverb, free, impulse)
7
unconscious(adjective, simple, natural, casual, impulsive)
5
impulsive(adjective, adverb, simple, natural, chance)
4
automatic(adjective, free, simple, fake, natural)
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APASmart Define. (2016). impromptu thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/impromptu/thesaurus/synonyms
ChicagoSmart Define. 2016. "impromptu thesaurus" https://smartdefine.org/impromptu/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, impromptu thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/impromptu/thesaurus/synonyms>.
MLASmart Define. "impromptu thesaurus" 28 January 2016. Web. 24 September 2026. <https://smartdefine.org/impromptu/thesaurus/synonyms>