C2 adjective /ˌɪndɪˈfætɪɡəbl̩/
indefatigable
unermüdlich
Meaning
persisting tirelessly; incapable of being fatigued
Example
Her indefatigable spirit kept the team motivated during the long project.
Ihr unermüdlicher Geist hielt das Team während des langen Projekts motiviert.