From Longman Dictionary of Contemporary Englishuntiringun‧tir‧ing /ʌnˈtaɪərɪŋ $ -ˈtaɪr-/ adjective WORK HARDworking very hard for a long period of time in order to do something – used to show approval SYN tireless untiring efforts to help the homeless
Examples from the Corpus
untiring• His general attitude is one of an untiring and immense courtesy and helpfulness.• Gonzales has been an untiring fighter for democracy.• Cardinal Basil Hume is untiring in his reminder that 12 million children under five die every year from hunger and disease.• A deceptively fragile and refined appearance belied her dedication and untiring industry in the cause of justice for women.• She was an untiring worker in the Medau cause, and is much missed. 