5
off the cuff(expression, adjective, idiom, free, unrehearsed)
5
quick(noun, adjective)
5
rash(noun, adjective, impulsive, unthinking)
5
undevised(adjective, planned, unintentional, accidental, inadvertent)
5
unmeant(adjective, planned, unknowing, unaware, unintentional)
5
unrehearsed(adjective, free, informal, casual, unqualified)
5
unthinking(adjective, impulsive, rash, unknowing, unaware)
4
ad-lib(adjective, free, simple, fake, informal)
4
aleatory(adjective, planned, accidental, unintended)
4
coincidental(adjective, chance, unintentional, accidental, unintended)
4
ignorant(adjective, impulsive, unknowing, unaware, unsuspecting)
4
makeshift(adjective, free, informal, casual, impulsive)
4
out of the blue(expression, adjective, idiom, adverb, unprepared)
4
rambling
4
serendipitous(adjective, chance, lucky, accidental, unpremeditated)
4
spot(adjective, chance, casual, irregular, planned)
4
unanticipated(adjective, adverb)
4
unconsidered(noun, adjective, chance, casual, irregular)
4
uncontrived(adjective, simple, natural, casual, impulsive)
4
unknowing(adjective, unaware, unintentional, unsuspecting)
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APASmart Define. (2015). unplanned thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/unplanned/thesaurus/synonyms
ChicagoSmart Define. 2015. "unplanned thesaurus" https://smartdefine.org/unplanned/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, unplanned thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/unplanned/thesaurus/synonyms>.
MLASmart Define. "unplanned thesaurus" 10 April 2015. Web. 26 September 2026. <https://smartdefine.org/unplanned/thesaurus/synonyms>