adj. 25B6; adjective TIRELESS, untiring, unwearied, unwearying, unflagging; determined, tenacious, dogged, single-minded, assiduous, industrious, unswerving, unfaltering, unshakeable, indomitable; persistent, relentless, unremitting.
INDEFATIGABLE
Meaning of INDEFATIGABLE in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012