safekeeping vs custody

safekeeping and custody both are nouns.

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

As nouns, custody is a hyponym of safekeeping; that is, custody is a word with a more specific, narrower meaning than safekeeping:

safekeeping: the responsibility of a guardian or keeper
custody: (with `in') guardianship over; in divorce cases it is the right to house and care for and discipline a child

Other hyponyms of safekeeping include hands.

safekeeping (noun)	custody (noun)
the responsibility of a guardian or keeper	holding by the police
	(with `in') guardianship over; in divorce cases it is the right to house and care for and discipline a child
	a state of being confined (usually for a short time)