Indefatigable – Synonym, Antonym, and Examples: Your Complete Guide In simple terms, indefatigable describes someone who is tireless, persistent, and shows unwavering effort despite challenges It's used to highlight extraordinary endurance and relentless energy—traits often admired in leaders, athletes, or activists
indefatigable - Wiktionary, the free dictionary 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