Webster's Revised Unabridged Dictionary · 1913

Pertinacy

Pertinacy , noun

[Latin pertinere to pertain. See Pertinence.]

The quality or state of being pertinent; pertinence. [Obsolete]

Pertinacy , noun

[Latin pertinacia, from pertinax. See Pertinacious.]

Pertinacity. [Obsolete] — Chaucer