legal duty vs responsibility

legal duty and responsibility both are nouns.

Word	Noun	Adjective	Verb	Adverb
legal duty	Yes	No	No	No
responsibility	Yes	No	No	No

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

legal duty: acts which the law requires be done or forborne
responsibility: the social force that binds you to the courses of action demanded by that force

Other hypernyms of legal duty include duty, obligation.

legal duty (noun)	responsibility (noun)
acts which the law requires be done or forborne	the social force that binds you to the courses of action demanded by that force
	a form of trustworthiness; the trait of being answerable to someone for something or being responsible for one's conduct
	the proper sphere or extent of your activities