dogged

assured, certain, dedicated, determined, firm, hell-bent, intent, positive, resolute, resolved, single-minded, sure

adamant, bullheaded, dogged, hardened, hardheaded, headstrong, implacable, indurate, mulish, obdurate, obstinate, opinionated, peevish, pertinacious, perverse, pigheaded, self-willed, stiff-necked, stubborn, unregenerate, unyielding, willful (or wilful)

unfaltering, unhesitating, unwavering

resistant, wayward, wrongheaded

constant, devoted, faithful, good, loyal, staunch (also stanch), steadfast, steady, true

indomitable, unconquerable

hard, inflexible, relentless, stern, unbending, unflinching, unrelenting

anal-retentive, obsessive

wayward, wrongheaded

determined, hell-bent, inexorable, persistent, relentless, resolved, set, single-minded, steadfast, stouthearted, tenacious, unflinching

firm, hard-line, hard-shell (or hard-shelled), iron, severe, stern, strict

hidebound, narrow-minded, rigid

bloody-minded [chiefly British], cantankerous

contrary, cussed

contumacious, disobedient, froward, insubordinate, intractable, recalcitrant, refractory, uncooperative, ungovernable, unmanageable, unruly

defiant, insurgent, mutinous

indomitable, invincible, unconquerable

confirmed, inveterate, unregenerate

demanding, exacting

persevering, persistent, tenacious

hard, hardheaded, headstrong, intractable, mulish, obdurate, opinionated, peevish, pertinacious, perverse, pigheaded, self-willed, stubborn, uncooperative, willful (or wilful)

merciless, ruthless, unforgiving