52 entries under adjective topic. ×

4
rash(sudden, unlooked-for, unhoped)
4
rushing(sudden, unlooked-for, unhoped)
4
spontaneous(sudden, unlooked-for, unhoped)
4
surprising(adverb, surprise, unexpected, unpredicted)
4
unexpectedly(adverb, unpredictable, surprising, subitaneous)
4
unplanned(adverb, surprise, unexpected, unprepared)
4
urgent(sudden, unlooked-for, unhoped)
4
without warning(expression, extraordinary, wonderful, surprise)
3
acute(sudden, unlooked-for, unhoped)
3
instant(sudden, unlooked-for, unhoped)
3
flashing(sudden, unlooked-for, unhoped)
3
fleeting(sudden, unlooked-for, unhoped)
3
instantaneous(sudden, unlooked-for, unhoped)
3
quickening(sudden, unlooked-for, unhoped)
3
reckless(sudden, unlooked-for, unhoped)
3
rushed(sudden, unlooked-for, unhoped)
3
sharp(sudden, unlooked-for, unhoped)
3
speedy(unpredictable, surprising, subitaneous)
3
subito(surprise, unexpected, sudden)
3
suddenly(adverb, surprising, not expected, not planned)
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APASmart Define. (2015). out of the blue thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/out_of_the_blue/thesaurus/synonyms
ChicagoSmart Define. 2015. "out of the blue thesaurus" https://smartdefine.org/out_of_the_blue/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2015, out of the blue thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/out_of_the_blue/thesaurus/synonyms>.
MLASmart Define. "out of the blue thesaurus" 3 August 2015. Web. 30 September 2026. <https://smartdefine.org/out_of_the_blue/thesaurus/synonyms>