This shirt has been washed so many times that it has sheered in some areas.

sheered 是动词 sheer 的过去分词形式。sheer 本意是"完全地、彻底地"，在纺织领域引申为"变得极薄、近乎透明"的意思，常用于描述织物因过度洗涤或磨损而变得透薄的状态。