wear (something) away
phrasal verb with wear verb uk/weər/ us/wer/ wore | worn
（使）磨损，磨掉
to become thin and disappear after repeated use or rubbing, or to cause something to become thin and disappear in this way
In some diseases, the protective layer in a joint wears away. 患某些疾病时，关节处的保护层会受到磨损。