11
immediate(noun, adjective, free, instinctive, sudden)
11
unconstrained(adjective, feature, characteristic, free, simple)
10
unrehearsed(adjective, free, plain, impulsive, unprepared)
10
emotional(noun, adjective, moving, passionate, violent)
10
extempore(adjective, free, simple, fake, informal)
10
knee-jerk(adjective, natural, emotional, impulsive, unconscious)
10
naive(adjective, simple, easy, pure, green)
10
spur-of-the-moment(noun, adjective, free, fake, informal)
10
unasked(adjective, feature, characteristic, free, regard)
10
unstudied(adjective, free, simple, easy, impulsive)
9
habitual(adjective, reasonable, common, ordinary, natural)
9
informal(adjective, free, simple, plain, relaxed)
9
impetuous(noun, adjective, moving, passionate, violent)
9
improvised(adjective, free, impulsive, willing, impulse)
9
reflex(adjective, natural, routine, impulsive, planned)
9
unbidden(adjective, free, deliberate, natural, impulsive)
9
unconscious(adjective, careless, casual, impulsive, willing)
9
casual(adjective, calm, free, fake, plain)
9
intuitive(adjective, reasonable, natural, instinctive, automatic)
9
normal(adjective, ordinary, natural, 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>