The Collaborative International Dictionary of English v.0.48:

Criticalness \Crit"ic*al*ness\, n.
   1. The state or quality of being critical, or of occurring at
      a critical time.
      [1913 Webster]

   2. Accuracy in examination or decision; exactness.
      [1913 Webster]

WordNet (r) 3.0 (2006):

criticalness
    n 1: a state of critical urgency [syn: criticality,
         criticalness, cruciality]