9
unmeditated(adjective, natural, thoughtless, impulse, instinctive)
9
unprepared(adjective, free, ready, impromptu, unplanned)
8
ad-lib(adjective, impulsive, willing, unprepared, impromptu)
8
intended(verb, adjective, feature, characteristic, free)
8
off the cuff(expression, adjective, idiom, free, impromptu)
8
regular(adjective, ordinary, normal, instinctive, automatic)
8
unlearned(adjective, natural, instinctive, untrained, automatic)
7
ad lib(expression, adjective, idiom, free, unrehearsed)
7
rash(noun, adjective, thoughtless, impulsive, unthinking)
7
uncompelled(adjective, free, deliberate, natural, impulsive)
7
unsolicited(adjective, for, uninvited, unsought)
7
visceral(adjective, natural, emotional, instinctive, automatic)
6
intentional(adjective, feature, characteristic, free, regard)
6
abrupt(adjective, thoughtless, impulsive, rash, unthinking)
6
accustomed(adjective, ordinary, normal, instinctive, automatic)
6
candid(simple, easy, honest, plain, pure)
6
congenital(adjective, reasonable, ordinary, instinctive, automatic)
6
easy(adjective, simple, plain, relaxed, casual)
6
hasty(adjective, thoughtless, impulsive, rash, unthinking)
6
inborn(adjective, reasonable, ordinary, instinctive, automatic)
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APASmart Define. (2015). spontaneous thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/spontaneous/thesaurus/synonyms
ChicagoSmart Define. 2015. "spontaneous thesaurus" https://smartdefine.org/spontaneous/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, spontaneous thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/spontaneous/thesaurus/synonyms>.
MLASmart Define. "spontaneous thesaurus" 3 August 2015. Web. 24 September 2026. <https://smartdefine.org/spontaneous/thesaurus/synonyms>