debenture vs official document

debenture and official document both are nouns.

Word	Noun	Adjective	Verb	Adverb
debenture	Yes	No	No	No
official document	Yes	No	No	No

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

debenture: a certificate or voucher acknowledging a debt
official document: (law) a document that states some contractual relationship or grants some right

Other hypernyms of debenture include instrument, legal document, legal instrument.

debenture (noun)	official document (noun)
a certificate or voucher acknowledging a debt	(law) a document that states some contractual relationship or grants some right
the ability of a customer to obtain goods or services before payment, based on the trust that payment will be made in the future