-f(t)nə̇s noun
( -es )
Etymology: Middle English swiftnes, from Old English, from swift (I) + -nes -ness
1. : the quality or state of being swift : speed , celerity
the swiftness of a lizard catching a fly — Vicki Baum
2. : the fact of being swift
when swiftness of action was indispensable to surprise