The Collaborative International Dictionary of English v.0.48:

Pertinacy \Per"ti*na*cy\, n. [L. pertinere to pertain. See
   Pertinence.]
   The quality or state of being pertinent; pertinence. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pertinacy \Per"ti*na*cy\, n. [L. pertinacia, fr. pertinax. See
   Pertinacious.]
   Pertinacity. [Obs.] --Chaucer.
   [1913 Webster]