unbendable

adjective [原级]一心一意的；不屈不挠的；坚定不移的

Pine, bamboo and plum are called the three friends in cold winter. They are planted beside tombs of national heros as a sign of unbendable loyalty to the country and people.
松、竹、梅被称为岁寒三友，它们被种植在民族英雄的坟墓旁，作为他们对国家和人民坚定不移的忠诚的象征。