tenacity

The state or quality of being tenacious: "Social styles developed in the 19th century withstand, with sporelike tenacity, all that the present century can throw at them" (Larry McMurty).

noun

The quality or state of being stubbornly unyielding: bullheadedness, doggedness, hardheadedness, mulishness, obstinacy, obstinateness, pertinaciousness, pertinacity, perverseness, perversity, pigheadedness, tenaciousness, willfulness. See resist/yield.

Definition: diligence, stubbornness
Antonyms: indifference, irresolution, slackness, weakness

n.

A certain quality of the human hand in its relation to the coin of the realm. It attains its highest development in the hand of authority and is considered a serviceable equipment for a career in politics. The following illustrative lines were written of a Californian gentleman in high political preferment, who has passed to his accounting:

    Of such tenacity his grip
    That nothing from his hand can slip.
    Well-buttered eels you may o'erwhelm
    In tubs of liquid slippery-elm
    In vain -- from his detaining pinch
    They cannot struggle half an inch!
    'Tis lucky that he so is planned
    That breath he draws not with his hand,
    For if he did, so great his greed
    He'd draw his last with eager speed.
    Nay, that were well, you say.  Not so
    He'd draw but never let it go!

The noun has one meaning:

Meaning #1: persistent determination
  Synonyms: doggedness, perseverance, persistence, persistency, tenaciousness, pertinacity