Synonyms and related words :
abruptness, improbability, inexpectance, inexpectancy, inexpectation, no expectation, nonexpectation, precipitance, precipitancy, precipitateness, precipitatousness, suddenness, the unforeseen, the unlooked-for, unanticipation, unforeseeableness, unpredictability, unpredictableness, unpreparedness, unreadiness