WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
the quality of happening with headlong haste or without warning
Word Usage
"“Then it dawned upon me with a certain suddenness,” he wrote in these pages in 1897, “that I was different from the others; or like, mayhap, in heart and life and longing, but shut out from their world by a vast veil.”"