The Collaborative International Dictionary
Pertinacy
Pertinacy \Per"ti*na*cy\, n. [L. pertinere to pertain. See Pertinence.] The quality or state of being pertinent; pertinence. [Obs.]
Pertinacy
Pertinacy \Per"ti*na*cy\, n. [L. pertinacia, fr. pertinax. See
Pertinacious.]
Pertinacity. [Obs.]
--Chaucer.
Wiktionary
pertinacy
Etymology 1 n. (obsolete form of pertinacity English) Etymology 2
n. The quality or state of being pertinent; pertinence.