persistent

Synonyms: assiduous bound bound and determined bulldogged constant continual dogged endless enduring firm fixed immovable incessant indefatigable in for long haul insistent interminable like bad penny never-ending obdurate obstinate perpetual perseverant persevering persisting pertinacious relentless repeated resolute steadfast steady sticky stubborn tenacious tireless unflagging unrelenting unremitting unshakable

Antonyms: lazy relenting surrendering yielding