51
abruptly(adverb, right, fast, straight, bang)
40
unexpectedly(adverb, unawares, abruptly, inexpectation, surprisingly)
24
instantaneously(adverb, instantaneity, earliness, inexpectation)
23
quickly(adjective, adverb, now, hastily, unexpectedly)
23
without warning(expression, idiom, adverb, unexpectedly, unawares)
17
out of the blue(expression, idiom, adverb, unexpectedly, abruptly)
15
hastily(adverb, unexpectedly, impulsively, rashly)
14
immediately(adverb, instantaneity, unexpectedly, earliness)
14
surprisingly(adverb, unexpectedly, unawares, ignorantly, inexpectation)
12
all at once(expression, idiom, adverb, instantaneity, unexpectedly)
12
precipitately
11
instantly
9
rapidly(adjective, adverb, hastily, unexpectedly, impulsively)
9
precipitously(adverb, hastily, unexpectedly, impulsively, abruptly)
9
sudden(adjective, adverb, unexpectedly, unawares, abruptly)
8
speedily(adverb, earliness)
8
sharply
7
forthwith(adverb, immediately, unexpectedly, unawares, earliness)
7
impetuously
7
impulsively
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APASmart Define. (2015). suddenly thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/suddenly/thesaurus/synonyms
ChicagoSmart Define. 2015. "suddenly thesaurus" https://smartdefine.org/suddenly/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, suddenly thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/suddenly/thesaurus/synonyms>.
MLASmart Define. "suddenly thesaurus" 13 April 2015. Web. 22 September 2026. <https://smartdefine.org/suddenly/thesaurus/synonyms>