from The Century Dictionary.
- To let out or release from being penned or dammed up; set free from a pen or confinement.
- To deprive of feathers.
from the GNU version of the Collaborative International Dictionary of English.
- transitive verb To release from a pen or from confinement.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- verb transitive To
releasefrom a pen.
from Wiktionary, Creative Commons Attribution/Share-Alike License
un- + pen
Once at 7K I quoted to him from Keats 'Endymion the lines about those people who "unpen their baaing vanities to browse away the comfortable green and juicy hay from human pastures."