65 entries under unplanned topic. ×

26
impromptu(adjective, adverb, simple, plain, informal)
20
spontaneous(noun, adjective, plain, impulsive, willing)
19
unrehearsed(adjective, adverb, plain, impulsive, prepared)
18
offhand(noun, adjective, simple, natural, chance)
17
unpremeditated(noun, adjective, impulsive, planned, impulse)
17
unprepared(adjective, spontaneous, unprepared, impromptu)
15
extempore(adjective, simple, informal, natural, chance)
13
improvised(adjective, simple, informal, natural, chance)
10
spur-of-the-moment(noun, adjective, impulsive, prepared, spontaneous)
10
ad-lib(adjective, simple, informal, natural, casual)
10
impulsive(noun, adjective, adverb, simple, natural)
9
off-the-cuff(adjective, adverb, simple, informal, natural)
8
unstudied(adjective, simple, natural, casual, impulsive)
7
casual(adjective, free, simple, natural, chance)
5
haphazard(adjective, unprepared, accidental, inadvertent)
5
undevised(adjective, unprepared, unintentional, accidental)
4
ad libitum(expression, adjective, idiom, adverb, informal)
4
improviso(adjective, free, casual, spontaneous, unprepared)
3
improvise(informal, impulse, extemporize, off-the-cuff)
3
involuntary(noun, adjective, simple, passionate, violent)
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APASmart Define. (2015). extemporaneous thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/extemporaneous/thesaurus/synonyms
ChicagoSmart Define. 2015. "extemporaneous thesaurus" https://smartdefine.org/extemporaneous/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2015, extemporaneous thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/extemporaneous/thesaurus/synonyms>.
MLASmart Define. "extemporaneous thesaurus" 13 April 2015. Web. 30 September 2026. <https://smartdefine.org/extemporaneous/thesaurus/synonyms>