indefatigable
adj. US //ˌɪndɪˈfætɪɡəbəɫ// UK //ˌɪndɪfˈætɪɡəbəl// in·de·fati·ga·ble
From Middle French, from Latin indēfatīgābilis (“untiring”), from in- (“not”) + dēfatīgō (“to tire out”).
From Middle French, from Latin indēfatīgābilis (“untiring”), from in- (“not”) + dēfatīgō (“to tire out”).
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