All the kids were afraid of him because he was known as the tiger of the neighborhood.

tiger 是名词，指"老虎"，这里用作比喻，形容某人像老虎一样凶猛可怕。在英语中常用动物名称来比喻人的性格特征，tiger 在这里比喻"令人生畏的、凶悍的人"。