The story
- Latin · derived frompertinax
- Old French · derived frompertinace
- English todaypertinacious
From pertinace + -ious, from Old French pertinace, from Latin pertinax, from per- (“very”) + tenax (“tenacious”).
Words from the same roots
Old Frenchpertinace all →
Latinpertinax all →
Etymology from Wiktionary, CC BY-SA 4.0.