The word "untiring" is an accepted and usable word in written English.
It is an adjective, and can be used to describe someone who never tires or gives up. For example, you could say, "She was an untiring warrior, fighting for her cause until victory was achieved."
Having an untiring, lightning-fast computer checking medical images would be as well.
They might even have gone into the Common Market without popular consent, had he not insisted on a referendum in 1975 (in which, dismayingly and despite his untiring "No" campaign, the people voted "Yes").
Through his untiring exertions, he managed to furnish enough game to keep the family in food, although he was not a first-rate hunter, his lore of books having early overcome the fondness and enthusiasm with which he had at first adopted the rifle".A second expedition to New Orleans led to his entering as clerk in a shop and mill at New Salem, Illinois.
Ready for continuing, untiring struggle against America's secular demons; or ready for resignation to some different call.
Tibetan nationalism remains a determined and untiring force.
He was a founder of the Fortschrittspartei (Progressive Party) and a determined and untiring opponent of Otto von Bismarck, who in 1865 challenged him to a duel, which he wisely declined.
He brought to the latter an untiring dedication in the gathering and assimilation of knowledge, an especial alertness to evidence of human fallibility and failure, and a powerful ordering intelligence supported by a delicate sense of aesthetic coherence.
"Only his care," he wrote during the Seven Years' War, "his untiring work, his scrupulously just policies, his great and admirable thriftiness and the strict discipline he introduced into the army which he himself had created, made possible the achievements I have so far accomplished".
That they did so well was largely because of untiring efforts by the capable secretary of the navy, Stephen Mallory.
To him it entailed obligations to be met only by untiring and conscientious work.
"Despite a valiant fight and the untiring efforts of the wonderful team at St Thomas's, he was overwhelmed.
