Each word has its own weight, but each word can be split into a root, and each root will also have a corresponding weight.

Suppose the word "iron-free shirt" has a weight, its roots "iron-free" and "shirt" will also have corresponding weights, but the weights are lower. Correspondingly, other keywords containing the root word "shirt" will also increase the weight of the entire keyword due to the increase in the weight of the root word "shirt", such as "stand-up collar shirt" and "long-sleeved shirt"