safekeeping vs duty

safekeeping and duty both are nouns.

Word	Noun	Adjective	Verb	Adverb
safekeeping	Yes	No	No	No
duty	Yes	No	No	No

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

safekeeping: the responsibility of a guardian or keeper
duty: the social force that binds you to the courses of action demanded by that force

Other hypernyms of safekeeping include obligation, responsibility.

safekeeping (noun)	duty (noun)
the responsibility of a guardian or keeper	the social force that binds you to the courses of action demanded by that force
	work that you are obliged to perform for moral or legal reasons
	a government tax on imports or exports