central vs of import

central is a noun but of import is not a noun.

Word	Noun	Adjective	Verb	Adverb
central	Yes	Yes	No	No
of import	No	Yes	No	No

central (noun)	of import (noun)
a workplace that serves as a telecommunications facility where lines from telephones can be connected together to permit communication

central (adjective)	of import (adjective)
in or near a center or constituting a center; the inner area	of great significance or value
serving as an essential component