1. (a.) Holding or adhering to any opinion, purpose, or design; resolute; obstinate\; as, pertinacious plotters; a pertinacious beggar.

2. (a.) Resolute; persevering; constant; steady.

assiduous balking balky bigoted bulldogged bulldoggish bulletheaded bullheaded case-hardened clamant clamorous constant continuing crying demanding diligent dogged dogmatic draining enduring exacting exigent exorbitant extortionate faithful fanatic fixed game gamy grasping gritty gutsy gutty hardheaded headstrong immutable importunate inalterable indefatigable indomitable industrious insistent instant intolerant invincible lasting loud loyal mettlesome mulish nervy never-tiring obstinate opinionated overzealous patient patient as Job permanent perseverant persevering persistent persisting perverse pigheaded plodding plucky plugging preoccupied pressing rapt red-blooded refractory relentless resolute restive sedulous self-willed set single-minded sleepless slogging spirited spiritful spunky stable steadfast steady stiff-necked strong-willed strongheaded stubborn sulky sullen taxing tenacious tireless tough unabating unconquerable uncooperative undaunted undiscouraged undrooping unfailing unfaltering unflagging unflinching unintermitting uninterrupted unnodding unregenerate unrelaxing unrelenting unremitting unshakable unsleeping unswerving untiring unwavering unwearied unwearying unwinking unyielding urgent utterly attentive weariless willful