22
spontaneous(noun, adjective, free, impulsive, planned)
21
impulsive(noun, adjective, rude, careless, natural)
19
unplanned(noun, adjective, free, chance, casual)
17
extemporaneous(noun, adjective, impulsive, planned, impulse)
17
involuntary(noun, adjective, natural, planned, ignorant)
15
impromptu(adjective, adverb, free, impulsive, planned)
14
unintentional(adjective, chance, planned, ignorant, hidden)
14
unthinking(adjective, careless, casual, impulsive, instinctive)
13
accidental(adjective, careless, chance, casual, planned)
13
casual(adjective, free, careless, chance, random)
13
offhand(noun, adjective, free, careless, casual)
12
natural(adjective, impulse, instinctive, automatic, involuntary)
11
extempore(adjective, free, planned, spontaneous, impromptu)
11
hasty(adjective, passionate, violent, thoughtless, impulsive)
11
instinctive(noun, adjective, rude, passionate, violent)
10
automatic(adjective, free, casual, planned, spontaneous)
10
inadvertent(adjective, careless, casual, thoughtless, unwise)
10
unintended(adjective, rude, careless, chance, casual)
10
unprepared(adjective, free, spontaneous, impromptu, unplanned)
10
unprompted(adjective, passionate, violent, impulse, abrupt)
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APASmart Define. (2015). Unpremeditated thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/unpremeditated/thesaurus/synonyms
ChicagoSmart Define. 2015. "Unpremeditated thesaurus" https://smartdefine.org/unpremeditated/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, Unpremeditated thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/unpremeditated/thesaurus/synonyms>.
MLASmart Define. "Unpremeditated thesaurus" 10 April 2015. Web. 20 September 2026. <https://smartdefine.org/unpremeditated/thesaurus/synonyms>