Fighting spirit — the will to fight or to compete; determination and competitive drive shown when facing a challenge.
彼は最後まで闘志を失わなかった。
He didn't lose his fighting spirit until the end.
新人選手が強い闘志を見せた。
The rookie showed strong fighting spirit.
敗北から立ち直り、再び闘志を燃やした。
He recovered from defeat and rekindled his fighting spirit.