adjective
definition
showing sustained enthusiastic action with unflagging vitality
etymology
Middle French, from Latin indefatigabilis, from in- ("not") + defatigare ("to fatigue"), from de- + fatigare ("to fatigue")
usage
Arnold had thought maybe today would be different, but twelve spitballs in his hair and a bowl of tapioca pudding down his shirt (and it wasn't even recess yet) proved that Helga would be indefatigable in her bullying, even on his birthday.
