Untiring means never seeming to get tired or give up, no matter how long or hard the work becomes. An untiring worker keeps going with the same energy and determination from start to finish. An untiring athlete practices hour after hour without losing focus or enthusiasm.

The word describes people who have remarkable stamina and persistence. Think of a researcher who spends years conducting experiments, facing failure after failure, but continues with untiring dedication until finally making a breakthrough. Or picture a teacher who answers the same question for the twentieth student with the same patience and care she showed the first.

Untiring is closely related to tireless, and the two words mean essentially the same thing. Both describe someone whose energy and commitment seem limitless. You might read about the untiring efforts of rescue workers searching for survivors, or the untiring devotion of a parent caring for a sick child.

When you're working on something difficult, like mastering a musical instrument or training for a competition, an untiring approach means you keep practicing and improving even when progress feels slow. The word celebrates people who refuse to quit.