UNWEARYING
indefatigable, tireless, unflagging, unwearying
(adjective) showing sustained enthusiastic action with unflagging vitality; “an indefatigable advocate of equal rights”; “a tireless worker”; “unflagging pursuit of excellence”
Source: WordNet® 3.1
Etymology
Adjective
unwearying (comparative more unwearying, superlative most unwearying)
Untiring; not becoming tired.
Synonyms: inexhaustible, tireless, untiring, unflagging, indefatigable
Source: Wiktionary
UNWEARY
Un*wea"ry, v. t. Etym: [1st pref. un- + weary.]
Definition: To cause to cease being weary; to refresh. [Obs.] Dryden.
Source: Webster’s Unabridged Dictionary 1913 Edition