unpin

Short definition from Wiktionary

Verb

1. 1
   To unfasten by removing a pin.
2. 2
   To detach (an icon, application, etc.) from the place where it was previously pinned.
3. 3
   To undo the pinning or fixing of (an array in memory, a security certificate, etc.) so that it can be modified again.
4. 4
   To get (a piece) out of a pin.