THESAURUS
without warning
abruptly, bang, by surprise, dash, hastily, impetuously, implausibly, improbably, impulsively, like a flash, like a thunderbolt, of a sudden, on short notice, plop, plump, plunk, pop, precipitantly, precipitately, precipitously, sharp, slap, smack, startlingly, sudden, suddenly, surprisingly, unanticipatedly, unawares, unexpectedly, unforeseeably, unpredictably, without notice
ROGET THESAURUS
without warning
Inexpectation
N
inexpectation, non-expectation, false expectation, miscalculation, surprise, sudden burst, thunderclap, blow, shock, start, bolt out of the blue, wonder, eye opener, unpleasant surprise, pleasant surprise, nonexpectant, surprised, unwarned, unaware, off one's guard, inattentive, unexpected, unanticipated, unpredicted, unlooked for, unforeseen, unhoped for, dropped from the clouds, beyond expectation, contrary to expectation, against expectation, against all expectation, out of one's reckoning, unheard of, startling, surprising, sudden, unpredictable, unforeseeable (unknowable), abruptly, unexpectedly, surprisingly, plump, pop, a l'improviste, unawares, without notice,
without warning, without a 'by your leave', like a thief in the night, like a thunderbolt, in an unguarded moment, suddenly, Int, heydey!, little did one think, little did one expect, nobody would ever suppose, nobody would ever think, nobody would ever expect, who would have thought? it beats the Dutch.