Indefatigable

ˌɪn.dɪˈfæ.tɪ.ɡə.bəl

adjective

able to work or continue for a long time without getting tired

The word 'indefatigable' comes from the Latin word 'indefatigabilis', which is derived from 'in-' (not) and 'defatigare' (to tire out). This word is used to describe someone who has an extraordinary amount of energy and can persist in their efforts without getting exhausted.

All night long the Martians were hammering and stirring, sleepless, indefatigable, at work upon the machines they were making ready, and ever and again a puff of greenish-white smoke whirled up to the starlit sky.

H. G. Wells

The War of the Worlds

To him, a stilted geometric love of arrangement was “system,” an indefatigable and feverish interest in the pettiest facets of day-to-day bureaucracy was “industry,” indecision when right was “caution,” and blind stubbornness when wrong, “determination.” And withal he wasted no money, killed no man needlessly, and meant extremely well.

Asimov, Isaac

Foundation 2 - Foundation and Empire

Observe, for example, the indefatigable, inevitable English utilitarians: how ponderously and respectably they stalk on, stalk along (a Homeric metaphor expresses it better) in the footsteps of Bentham, just as he had already stalked in the footsteps of the respectable Helvetius!

Friedrich Nietzsche

Beyond Good and Evil

But not content with this good deed, the indefatigable house again bestirred itself: Samuel and all his Sons—how many, their mother only knows—and under their immediate auspices, and partly, I think, at their expense, the British government was induced to send the sloop-of-war Rattler on a whaling voyage of discovery into the South Sea.

Herman Melville

Moby Dick

Faria has dreamed this; the Cardinal Spada buried no treasure here; perhaps he never came here, or if he did, Caesar Borgia, the intrepid adventurer, the stealthy and indefatigable plunderer, has followed him, discovered his traces, pursued them as I have done, raised the stone, and descending before me, has left me nothing.” He remained motionless and pensive, his eyes fixed on the gloomy aperture that was open at his feet.

Alexandre Dumas

The Count of Monte Cristo

Incontestably fond of his country, but preferring his family; assuming more domination than authority and more authority than dignity, a disposition which has this unfortunate property, that as it turns everything to success, it admits of ruse and does not absolutely repudiate baseness, but which has this valuable side, that it preserves politics from violent shocks, the state from fractures, and society from catastrophes; minute, correct, vigilant, attentive, sagacious, indefatigable; contradicting himself at times and giving himself the lie; bold against Austria at Ancona, obstinate against England in Spain, bombarding Antwerp, and paying off Pritchard; singing the Marseillaise with conviction, inaccessible to despondency, to lassitude, to the taste for the beautiful and the ideal, to daring generosity, to Utopia, to chimaeras, to wrath, to vanity, to fear; possessing all the forms of personal intrepidity; a general at Valmy; a soldier at Jemappes; attacked eight times by regicides and always smiling.

Victor Hugo

Les Misérables

My father’s care and attentions were indefatigable, but he did not know the origin of my sufferings and sought erroneous methods to remedy the incurable ill.

Mary Wollstonecraft Shelley

Frankenstein; Or, The Modern Prometheus

“But I can guess,” continued my indefatigable sister.

Agatha Christie

The Murder of Roger Ackroyd

A strangely dirty and irregular life these dark-eyed, dark-haired, half-happy savages lead in this clean wilderness—starvation and abundance, deathlike calm, indolence, and admirable, indefatigable action succeeding each other in stormy rhythm like winter and summer.

John Muir

My First Summer in the Sierra

Honour to those indefatigable spirits who consecrate their vigils to the amelioration or to the alleviation of their kind!

Gustave Flaubert

Madame Bovary

who shall tempt with wandering feet The dark, unbottomed, infinite Abyss, And through the palpable obscure find out His uncouth way, or spread his aery flight, Upborne with indefatigable wings Over the vast abrupt, ere he arrive The happy isle?

John Milton

Paradise Lost

All this I say, exalted and esteemed lady, because it seems to me that for us to remain any longer in this castle now is useless, and may be injurious to us in a way that we shall find out some day; for who knows but that your enemy the giant may have learned by means of secret and diligent spies that I am going to destroy him, and if the opportunity be given him he may seize it to fortify himself in some impregnable castle or stronghold, against which all my efforts and the might of my indefatigable arm may avail but little?

Miguel de Cervantes Saavedra

Don Quixote

Colonel Cathcart was indefatigable that way, an industrious, intense, dedicated military tactician who calculated day and night in the service of himself.

Heller, Joseph

Catch-22

A nation of courageous, hardy, indefatigable women, dwelling apart from men, permitting only a short temporary intercourse, for the purpose of renovating their numbers, burning out their right breast with a view of enabling themselves to draw the bow freely; this was at once a general type, stimulating to the fancy of the poet, and a theme eminently popular with his hearers.

Homer

The Iliad

In the meantime Ferrier having recovered from his privations, distinguished himself as a useful guide and an indefatigable hunter.

Arthur Conan Doyle

A Study in Scarlet