Without warning or announcement.

synonyms: unannounced, unheralded.

Roget 508: nonexpectant^†; surprised etc. v.; unwarned, unaware; off one's guard; inattentive 458.    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 etc. (exceptional) 83; startling, surprising; sudden etc. (instantaneous) 113.    unpredictable, unforeseeable (unknowable) 519.    ... show more