Pertinacious

Part of speech: adjective (a.)

1. Holding or adhering to any opinion, purpose, or design, with obstinacy; perversely persistent; obstinate; as, pertinacious plotters; a pertinacious beggar.

2. Resolute; persevering; constant; steady. Diligence is a steady, constant, and pertinacious study. South.

Synonyms: Obstinate; stubborn; inflexible; unyielding; resolute; determined; firm; constant; steady. Per`ti*na"cious*ly, adv. Per`ti*na"cious*ness, n.