low-pitched vs deep

low-pitched is not a noun while deep is a noun.

Word	Noun	Adjective	Verb	Adverb
low-pitched	No	Yes	No	No
deep	Yes	Yes	No	Yes

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

low-pitched (adjective)	deep (adjective)
used of sounds and voices; low in pitch or frequency	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
set at a low angle or slant	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