unrelenting
adjective formal uk/ˌʌn.rɪˈlen.tɪŋ/ us/ˌʌn.rɪˈlen.t̬ɪŋ/
坚定不移的；不松懈的；不屈不挠的
extremely determined; never becoming weaker or admitting defeat
She will be remembered as an unrelenting opponent of racial discrimination. 她不屈不挠地反对种族歧视，将会为人所铭记。