indefatigable

Definition

Extremely persistent and untiring.

Etymology

From Middle French, from Latin indēfatīgābilis (“untiring”), from in- (“not”) + dēfatīgō (“to tire out”).

Example Sentences

• "[...] But he was at the ſame Time an excellent Scholar, and moſt indefatigable in teaching the two Lads."
• "He was respected by all who knew him for his integrity and indefatigable attention to public business."
• "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."