33 entries under spontaneous topic. ×

21
impulsive(noun, adjective, rude, careless, natural)
17
extemporaneous(noun, adjective, impulsive, planned, impulse)
15
impromptu(adjective, adverb, free, impulsive, planned)
13
offhand(noun, adjective, free, careless, casual)
11
extempore(adjective, free, planned, impromptu)
11
instinctive(noun, adjective, rude, passionate, violent)
10
automatic(adjective, free, casual, planned)
10
unprepared(adjective, free, impromptu, unplanned)
10
unstudied(adjective, free, casual, impromptu)
9
spur-of-the-moment(noun, adjective, free, impulsive)
8
unconscious(adjective, careless, natural, casual, thoughtless)
7
improvised(adjective, free, casual, impulsive, impulse)
5
extemporary(adjective, free, casual, impulsive)
5
unrehearsed(adjective, free, impulsive, unprepared)
4
ad-lib(adjective, unprepared, impromptu, unplanned)
3
extemporized(adjective, unprepared, unplanned, unrehearsed)
3
headlong(noun, adjective, passionate, violent, thoughtless)
3
hit-or-miss(adjective, careless, chance, casual)
3
unarranged(adjective, unprepared, unplanned, unrehearsed)
2
improv(free, informal, casual, unprepared)
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APASmart Define. (2015). unpremeditated thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/unpremeditated/thesaurus/synonyms
ChicagoSmart Define. 2015. "unpremeditated thesaurus" https://smartdefine.org/unpremeditated/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2015, unpremeditated thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/unpremeditated/thesaurus/synonyms>.
MLASmart Define. "unpremeditated thesaurus" 10 April 2015. Web. 30 September 2026. <https://smartdefine.org/unpremeditated/thesaurus/synonyms>