tire·less 
(tīrlĭs)
(tīrlĭs)adj.
Having or showing a capacity for persistent effort; not tiring or relenting: a tireless advocate; tireless efforts.
tireless·ly adv.
tireless·ness n.
Synonyms: tireless, indefatigable, unflagging, untiring, unwearied, weariless
These adjectives mean having or showing a capacity for persistent or prolonged effort: a tireless worker; an indefatigable advocate of human rights; unflagging pursuit of excellence; untiring energy; an unwearied researcher; a weariless defender of freedom of the press.
These adjectives mean having or showing a capacity for persistent or prolonged effort: a tireless worker; an indefatigable advocate of human rights; unflagging pursuit of excellence; untiring energy; an unwearied researcher; a weariless defender of freedom of the press.