writ vs legal instrument

writ and legal instrument both are nouns.

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

As nouns, legal instrument is a hypernym of writ; that is, legal instrument is a word with a broader meaning than writ:

writ: (law) a legal document issued by a court or judicial officer
legal instrument: (law) a document that states some contractual relationship or grants some right

Other hypernyms of writ include instrument, legal document, official document.

writ (noun)	legal instrument (noun)
(law) a legal document issued by a court or judicial officer	(law) a document that states some contractual relationship or grants some right