resignation vs written document

resignation and written document both are nouns.

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

As nouns, written document is a hypernym of resignation; that is, written document is a word with a broader meaning than resignation:

resignation: a formal document giving notice of your intention to resign
written document: writing that provides information (especially information of an official nature)

Other hypernyms of resignation include document, papers.

resignation (noun)	written document (noun)
the act of giving up (a claim or office or possession etc.)	writing that provides information (especially information of an official nature)
a formal document giving notice of your intention to resign
acceptance of despair