tireless

The gun advocates are tireless and they bet on suburban swing voters forgetting about their anger.

In the course of time, as the result of Grenfell's tireless efforts, a marvelous change for the better took place.

These tireless birds seem to pass almost the entire day on the wing in pursuit of insects upon which they feed almost exclusively.

Not only was he a tireless worker, but he was quick as a flash to see what was needed.

She, with her tireless energies, was not one to cry forever over milk hopelessly spilt.

Rand was quick at divining men, and now he thought, "This man would make a tireless enemy."