Synonyms for Abruptness (same or very similar meaning)
WordNet sense 1 (the property possessed by a slope that is very steep):
steepness, precipitousnessWordNet sense 2 (an abrupt discourteous manner):
brusqueness, curtness, gruffness, shortnessWordNet sense 3 (the quality of happening with headlong haste or without warning):
suddenness, precipitancy, precipitance, precipitatenessFrom the ODE community, based on WordNetadd/edit