concordat vs written agreement

concordat and written agreement both are nouns.

Word	Noun	Adjective	Verb	Adverb
concordat	Yes	No	No	No
written agreement	Yes	No	No	No

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

concordat: a signed written agreement between two or more parties (nations) to perform some action
written agreement: a legal document summarizing the agreement between parties

concordat (noun)	written agreement (noun)
a signed written agreement between two or more parties (nations) to perform some action	a legal document summarizing the agreement between parties