written document vs article

written document and article both are nouns.

Word	Noun	Adjective	Verb	Adverb
written document	Yes	No	No	No
article	Yes	No	Yes	No

written document (noun)	article (noun)
writing that provides information (especially information of an official nature)	one of a class of artifacts
	nonfictional prose forming an independent part of a publication
	(grammar) a determiner that may indicate the specificity of reference of a noun phrase
	a separate section of a legal document (as a statute or contract or will)

written document (verb)	article (verb)
	bind by a contract; especially for a training period