The Collaborative International Dictionary of English v.0.48:

Nimbleness \Nim"ble*ness\, n.
   The quality of being nimble; lightness and quickness in
   motion; agility; swiftness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nimbleness
    n 1: intelligence as revealed by quickness and alertness of
         mind; "nimbleness of wit and imagination" [syn:
         nimbleness, mental dexterity]
    2: the gracefulness of a person or animal that is quick and
       nimble [syn: agility, legerity, lightness,
       lightsomeness, nimbleness]