independent vs self-sustaining

independent is a noun but self-sustaining is not a noun.

Word	Noun	Adjective	Verb	Adverb
independent	Yes	Yes	No	No
self-sustaining	No	Yes	No	No

independent (noun)	self-sustaining (noun)
a writer or artist who sells services to different employers without a long-term contract with any of them
a neutral or uncommitted person (especially in politics)

independent (adjective)	self-sustaining (adjective)
free from external control and constraint	able to provide for your own needs without help from others
(of a clause) capable of standing syntactically alone as a complete sentence
(of political bodies) not controlled by outside forces
not controlled by a party or interest group