11
accidentally(adverb, circumstance, accident, unexpectedly, casually)
9
casually(adverb, circumstance, unexpectedly, accidentally)
7
incidentally
5
unexpectedly(adverb, circumstance, accident)
4
fortuitously(adjective, adverb, accident, casually, fortunately)
4
haphazardly(adjective, adverb)
4
spontaneously
3
by a fluke(expression, idiom, adverb, accident, fortunately)
3
by accident(expression, idiom, adverb, fortunately, luckily)
3
circumstantially
3
for some reason(expression, idiom, adverb, accident)
3
perchance
3
random(chance, unplanned, unpremeditated)
3
randomly
3
unintentionally(adjective, adverb, accident, fortunately, luckily)
2
at random
2
chance(unplanned, unpremeditated)
2
erratically
2
indiscriminately
2
irregularly
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APASmart Define. (2015). by chance thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/by_chance/thesaurus/synonyms
ChicagoSmart Define. 2015. "by chance thesaurus" https://smartdefine.org/by_chance/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, by chance thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/by_chance/thesaurus/synonyms>.
MLASmart Define. "by chance thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/by_chance/thesaurus/synonyms>