INDEFAT'IGABLE, adjective [Latin indefatigabilis; in and defatigo, fatigo, to fatigue.] Unwearied; not tired; not exhausted by labor; not yielding to fatigue; as indefatigable exertions; indefatigable attendance or perseverance. Upborne with indefatigable wings.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI