The Collaborative International Dictionary of English v.0.48:

Doggedness \Dog"ged*ness\, n.
   1. Sullenness; moroseness. [R.]
      [1913 Webster]

   2. Sullen or obstinate determination; grim resolution or
      persistence.
      [1913 Webster]

WordNet (r) 3.0 (2006):

doggedness
    n 1: persistent determination [syn: doggedness,
         perseverance, persistence, persistency, tenacity,
         tenaciousness, pertinacity]