Working hard at something over a long time without ever seeming to get tired or give up. It describes the kind of person who is still going long after everyone else has stopped, and it is almost always a compliment — it praises determination, not just energy.

Working hard at something over a long time長時間很努力做一件事，without ever seeming to get tired or give up而且看起來從來不會累或放棄。It它 describes the kind of person形容的是那種人，who is still going long after everyone else has stopped別人都停下來很久了，他還在繼續做，and而且 it it is almost always a compliment幾乎都是稱讚的話——it it praises determination, not just energy稱讚的是毅力，不只是體力。

It attaches especially to work done for a cause: a tireless campaigner, a tireless defender of human rights, her tireless work for the charity. It is also used of the effort itself: tireless efforts, tireless dedication.

It它 attaches especially to work done for a cause特別常搭配為某個理念做的事：a tireless campaigner像不知疲倦的運動者、a tireless defender of human rights不屈不撓的人權捍衛者、her tireless work for the charity她為慈善機構所做的不懈努力。It它 is also used of the effort itself也可以用來形容努力本身：tireless efforts像 tireless efforts、tireless dedication tireless dedication。

Notice that it does not literally claim the person never feels tired — of course they do. What it means is that their tiredness never stops them, which is why it sounds like praise rather than a medical description.

Notice要注意 that it does not literally claim the person never feels tired它並不是字面上說這個人從來不會累——of course they do他們當然還是會累。What這個字真正的意思是 it means is that their tiredness never stops them是他們的疲累從來不會讓他們停下來，which這也是為什麼 is why it sounds like praise rather than a medical description它聽起來像稱讚，而不是在描述身體狀況。

The related adverb is "tirelessly" ("she worked tirelessly for years"), and the noun is "tirelessness", which is rarer.

The related adverb相關的副詞 is "tirelessly"是 "tirelessly"（"she worked tirelessly for years"像「she worked tirelessly for years」），and而 the noun名詞 is "tirelessness"是 "tirelessness"，which這個字 is rarer比較少見。