努める[tsutomeru] to endeavor (endeavour)
努めて[tsutomete] as much as possible
努力[doryoku] great effort
努力家[doryokuka] hard worker
努む[rikimu] to strain

極力努める[kyokuryokutsutomeru] to do one's best
努力も空しく[doryokumomunashiku] after efforts in vain
努力賞[doryokushou] prize awarded for a person's effort
実らなかった努力[minoranakattadoryoku] fruitless (resultless) efforts
奮励努力[funreidoryoku] making strenuous efforts