legal document vs legal instrument

legal document and legal instrument both are nouns.

Word	Noun	Adjective	Verb	Adverb
legal document	Yes	No	No	No
legal instrument	Yes	No	No	No

As nouns, legal document and legal instrument are synonyms defined as:

legal document and legal instrument: (law) a document that states some contractual relationship or grants some right

Other synonyms of legal document include instrument, official document.

legal document (noun)	legal instrument (noun)
(law) a document that states some contractual relationship or grants some right	(law) a document that states some contractual relationship or grants some right