maelstrom vs Charybdis

maelstrom and Charybdis both are nouns.

Word	Noun	Adjective	Verb	Adverb
maelstrom	Yes	No	No	No
Charybdis	Yes	No	No	No

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

maelstrom: a powerful circular current of water (usually the result of conflicting tides)
Charybdis: (Greek mythology) a ship-devouring whirlpool lying on the other side of a narrow strait from Scylla

maelstrom (noun)	Charybdis (noun)
a powerful circular current of water (usually the result of conflicting tides)	(Greek mythology) a ship-devouring whirlpool lying on the other side of a narrow strait from Scylla