Davy Jones vs Davy Jones's locker

Davy Jones and Davy Jones's locker both are nouns.

Word	Noun	Adjective	Verb	Adverb
Davy Jones	Yes	No	No	No
Davy Jones's locker	Yes	No	No	No

As nouns, Davy Jones and Davy Jones's locker are synonyms defined as:

Other synonyms of Davy Jones include ocean bottom, ocean floor, sea bottom, sea floor, seabed.

Davy Jones (noun)	Davy Jones's locker (noun)
the bottom of a sea or ocean	the bottom of a sea or ocean