bar vs block off

bar is a noun but block off is not a noun.

Word	Noun	Adjective	Verb	Adverb
bar	Yes	No	Yes	No
block off	No	No	Yes	No

As verbs, bar and block off are synonyms defined as:

Other synonyms of bar include barricade, block, block up, blockade, stop.

As verbs, block off is a hyponym of bar; that is, block off is a word with a more specific, narrower meaning than bar:

Other hyponyms of bar include close off, shut off, close.

bar (noun)	block off (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)	block off (verb)
prevent from entering; keep out	obstruct access to
render unsuitable for passage	render unsuitable for passage
secure with, or as if with, bars	block off the passage through
expel, as if by official decree