deep vs deep-water

deep is a noun but deep-water is not a noun.

Word	Noun	Adjective	Verb	Adverb
deep	Yes	Yes	No	Yes
deep-water	No	Yes	No	No

deep (noun)	deep-water (noun)
a long steep-sided depression in the ocean floor
literary term for an ocean
the central and most intense or profound part

deep (adjective)	deep-water (adjective)
having great spatial extension or penetration downward or inward from an outer surface or backward or laterally or outward from a center; sometimes used in combination	of or carried on in waters of great depth
relatively deep or strong; affecting one deeply
exhibiting great cunning usually with secrecy
strong; intense
very distant in time or space
difficult to penetrate; incomprehensible to one of ordinary understanding or knowledge
of an obscure nature
intense or extreme
large in quantity or size
with head or back bent low
having or denoting a low vocal or instrumental range
marked by depth of thinking
relatively thick from top to bottom
extending relatively far inward
(of darkness) densely dark