4
interior(adjective, gut, intuitive)
4
internal(adjective, gut, intuitive)
4
optional(adjective, free, deliberate, natural, willing)
4
perceptive(adjective, instinctive, intuitive)
4
reckless(noun, adjective, careless, casual, thoughtless)
4
uncalculated(chance, unwilling, obligatory, accidental, compulsory)
4
unconsidered(noun, careless, casual, thoughtless, impetuous)
4
uncontrolled(adjective, reasonable, relaxed, wild, common)
4
understood(adjective, instinctive, intuitive)
4
unintended(chance, unwilling, unplanned, obligatory, accidental)
4
unreflecting(adjective, impulsive, rash, unthinking, instinctive)
4
unscripted(adjective, unprepared, impromptu, unplanned, unrehearsed)
4
unwritten
4
viscerous(adjective, gut, intuitive)
3
open(adjective, calm, simple, easy, informal)
3
complimentary(adjective, feature, characteristic, free, gratis)
3
designful(adjective, feature, characteristic, free, deliberate)
3
discretionary
3
elected(adjective, feature, characteristic, free, deliberate)
3
frank(adjective, open, simple, easy, careless)
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APASmart Define. (2015). spontaneous thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/spontaneous/thesaurus/synonyms
ChicagoSmart Define. 2015. "spontaneous thesaurus" https://smartdefine.org/spontaneous/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, spontaneous thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/spontaneous/thesaurus/synonyms>.
MLASmart Define. "spontaneous thesaurus" 3 August 2015. Web. 25 September 2026. <https://smartdefine.org/spontaneous/thesaurus/synonyms>