2
improviso(adjective, free, casual, spontaneous, unprepared)
2
informal(adjective, free, casual, snap, spontaneous)
2
instantaneous(adjective, impulsive)
2
last-minute
2
made-up(adjective, free, informal, casual, snap)
2
oblivious(careless, thoughtless, ignorant, unaware, inconsiderate)
2
off-the-cuff(adjective, chance, spontaneous, unprepared, impromptu)
2
reckless(noun, adjective, careless, casual, thoughtless)
2
scratch
2
subconscious(ignorant, hidden, unconscious, unaware, oblivious)
2
unaware(ignorant, hidden, unconscious, oblivious, subconscious)
2
undeliberate(ignorant, hidden, unconscious, unaware, oblivious)
2
unheeding(adjective, careless, thoughtless, unwise, ignorant)
2
unmindful(careless, thoughtless, ignorant, hidden, unconscious)
2
unthought(unplanned, accidental, inadvertent)
2
winging it(expression, free, violent, casual, unrehearsed)
1
advanced
1
aimless(careless, chance, casual, random, haphazard)
1
aleatory
1
artless
11 years ago|6.1k views|share |citing 
APASmart Define. (2015). unpremeditated thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/unpremeditated/thesaurus/synonyms
ChicagoSmart Define. 2015. "unpremeditated thesaurus" https://smartdefine.org/unpremeditated/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2015, unpremeditated thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/unpremeditated/thesaurus/synonyms>.
MLASmart Define. "unpremeditated thesaurus" 10 April 2015. Web. 28 September 2026. <https://smartdefine.org/unpremeditated/thesaurus/synonyms>