(of animals, livestock, etc) to release from a pen or enclosure
2.
(of ideas or emotions) to vent, to let out
unpen in American English
(unˈpen)
transitive verbWord forms: -penned, -penning
to release from confinement
Word origin
[1585–95; un-2 + pen2]This word is first recorded in the period 1585–95. Other words that entered Englishat around the same time include: corridor, filament, sine, switch, titularun- is a prefix freely used in English to form verbs expressing a reversal of some actionor state, or removal, deprivation, release, etc. (unbend; uncork; unfasten; etc.), or to intensify the force of a verb already having such a meaning (unloose)