To Be Rubbed
To Be Grazed, To Be Scraped
intransitive verb, ichidan verb
This is an intransitive version of 擦る, so it means to be rubbed. It often implies damage, in which case it can mean to be grazed or to be scraped, like when your knee gets grazed against a rough wall.
You really don’t want your knee to be grazed. If it happens, you are gonna sue (す). But the cost (こす) of suing is pretty high, so be careful not to get grazed in the first place!
Depending on which reading you use, the nuance changes slightly. For example, すれる is the usual choice when you’re talking about your grazed knees or worn out jeans. For other uses, they are often interchangeable.
ペティコートは、スカートが肌と擦れることを防ぎます。
Petticoats prevent skirts from rubbing against your skin.