What does it mean that the spring thunder is fierce and the emperor Tuqi's family is fierce?

This poem was written by Zhu Yuanzhang on the spur of the moment when he went to visit a temple on Nanjing Purple Mountain after defeating the army led by Chen Youliang. The murderous look in the poem is completely exposed, and it seems that there is still a trace of the blood of the defeated soldiers that has not been exhausted between the lines. It is recorded that this poem was drafted before Zhu Yuanzhang rebelled and seized power, and it also shows from the side that Zhu Yuanzhang, the founding emperor of the Ming Dynasty, hated the style and determination of the emperor at that time.

Full text:

The west wind is spreading eastward, the yellow flowers are blooming, and the children's flute in Niubei Village is just right.

People who used to know leaning against the building got up every time they heard the moon.

In autumn, the Cangjiang River is muddy, and the early light of red leaves sets off the late China.

The fierce weather was accompanied by spring thunder, and the fierce emperor slaughtered seven families.