bar vs unbar

bar is a noun but unbar is not a noun.

Word	Noun	Adjective	Verb	Adverb
bar	Yes	No	Yes	No
unbar	No	No	Yes	No

bar (noun)	unbar (noun)
the act of preventing
a rigid piece of metal or wood; usually used as a fastening or obstruction or weapon
an obstruction (usually metal) placed at the top of a goal
a room or establishment where alcoholic drinks are served over a counter
a counter where you can obtain food or drink
a block of solid substance (such as soap or wax)
(law) a railing that encloses the part of the courtroom where the judges and lawyers sit and the case is tried
a heating element in an electric fire
a horizontal rod that serves as a support for gymnasts as they perform exercises
a narrow marking of a different color or texture from the background
musical notation for a repeating pattern of musical beats
the body of individuals qualified to practice law in a particular jurisdiction
a submerged (or partly submerged) ridge in a river or along a shore
(meteorology) a unit of pressure equal to a million dynes per square centimeter

bar (verb)	unbar (verb)
prevent from entering; keep out	remove a bar from (a door)
render unsuitable for passage
secure with, or as if with, bars
expel, as if by official decree