pierceless
/ˈpɪəsləs/adjective
1Incapable of being pierced; impenetrable. poetic. Now rare.
2 North American. Of or designating an earring or other piece of jewellery, which is clipped or screwed on, rather than being worn through a piercing.
Origin
Mid 18th century. From pierce + -less. Compare earlier piercelessness.