INDEFATIGABLE
INDEFATIGABLE(adj): never giving up or getting tired of doing something.
Synonyms- Inexhaustible, tireless, unflagging, untiring, weariless, energetic, active, conscientious
Antonyms- exhaustible, weary, lethargic, fatigued, tired, sluggish, drained
Sentence usage- The Techouse Library offers an indefatigable array of services to its beneficiaries.
Phrase- tirelessly persistent.
Idiom- going the extra mile.