never giving up or getting tired of doing something 不屈不挠的；不知疲倦的 an indefatigable defender of human rights 不屈不挠的人权捍卫者 She was indefatigable in her search for the truth. 她一直在寻找真理。
Word Originearly 17th cent.: from French, or from Latin indefatigabilis, from in- ‘not’ + de- ‘away, completely’ + fatigare ‘wear out’.