pertinacious

From Latin pertinax, from per- (“very”) + tenax (“tenacious”).

• (UK) IPA^(key): /ˌpɜːtɪˈneɪʃəs/
• (US) enPR: pûr-tn-ā'shəs, IPA^(key): /pɝtn̩ˈeɪʃəs/
• Rhymes: -eɪʃəs

pertinacious (comparative more pertinacious, superlative most pertinacious)

1. Holding tenaciously to an opinion or purpose.
   • 1884, Henry James, "The Path of Duty" in The English Illustrated Magazine 2(15): 240–256.

     He would really have to make up his mind to care for his wife or not to care for her. What would Lady Vandeleur say to one alternative, and what would little Joscelind say to the other? That is what it was to have a pertinacious father and to be an accommodating son.

2. Stubbornly resolute or tenacious.

• See also Thesaurus:obstinate

• pertinaciousness
• pertinacity