clip on
1. An earring that clips onto the earlobe, as opposed to being inserted through a piercing. Jen never got her ears pierced, so we're going to need to find her some nice clip ons for her wedding day.
2. A necktie that clips onto the collar, as opposed to being tied. When I was a kid, I used to wear a clip on before I knew how to tie a tie.
clip on(to) (someone or something)
To attach something to someone or something else by using a clip. A noun or pronoun can be used between "clip" and "on." Clip on your ID badge before you leave so that you can get back into the building. I clipped the doctor's note onto the rest of my paperwork.