1
startling(extraordinary, wonderful, shocking, astonishing, astounding)
1
stunning(extraordinary, wonderful, shocking, astonishing, astounding)
1
uncalculated(adjective, surprise, unexpected, sudden)
1
unlikely(adverb, not expected, not planned, unhoped, uncontemplated)
1
unlooked for(adjective, surprise, unexpected, sudden)
1
unpredictable(extraordinary, wonderful, shocking, astonishing, astounding)
1
untimely(adverb, not expected, not planned, unhoped, uncontemplated)
0
aback
0
abruptly
0
ad hoc(expression, unprepared)
0
asudden
0
expeditious
0
extraordinary(wonderful, shocking, astonishing, astounding)
0
fleet
0
forthwith
0
impromptu
0
on spur of moment
0
precipitant
0
precipitate
0
precipitous
11 years ago|9.3k views|share |citing 
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>