40 entries under simple topic. ×

26
impromptu(adjective, adverb, plain, informal)
18
offhand(noun, adjective, natural, chance)
15
extempore(adjective, informal, natural, chance)
13
improvised(adjective, informal, natural, chance)
10
ad-lib(adjective, informal, natural, casual)
10
impulsive(noun, adjective, adverb, natural)
9
off-the-cuff(adjective, adverb, informal, natural)
9
unplanned(noun, adjective, informal, natural)
8
unstudied(adjective, natural, casual, impulsive)
7
casual(adjective, free, natural, chance)
7
makeshift(adjective, free, casual, crude)
4
automatic(adjective, passionate, violent, natural)
4
instinctive(noun, adjective, passionate, violent)
4
uncontrived(adjective, natural, casual, impulsive)
4
unprompted(adjective, plain, violent, natural)
3
involuntary(noun, adjective, passionate, violent)
3
natural(adjective, casual, impulsive, willing)
3
unintentional(adjective, natural, chance, casual)
2
impetuous(noun, adjective, passionate, violent)
2
unconscious(adjective, natural, casual, impulsive)
<12>
11 years ago|9.3k views|share |citing 
APASmart Define. (2015). extemporaneous thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/extemporaneous/thesaurus/synonyms
ChicagoSmart Define. 2015. "extemporaneous thesaurus" https://smartdefine.org/extemporaneous/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, extemporaneous thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/extemporaneous/thesaurus/synonyms>.
MLASmart Define. "extemporaneous thesaurus" 13 April 2015. Web. 26 September 2026. <https://smartdefine.org/extemporaneous/thesaurus/synonyms>