shallow vs knee-deep

shallow is a noun but knee-deep is not a noun.

Word	Noun	Adjective	Verb	Adverb
shallow	Yes	Yes	Yes	No
knee-deep	No	Yes	No	Yes

shallow (noun)	knee-deep (noun)
a stretch of shallow water

shallow (adjective)	knee-deep (adjective)
lacking physical depth; having little spatial extension downward or inward from an outer surface or backward or outward from a center	coming only to the ankle or knee
not deep or strong; not affecting one deeply
lacking depth of intellect or knowledge; concerned only with what is obvious

shallow (verb)	knee-deep (verb)
become shallow
make shallow

shallow (adverb)	knee-deep (adverb)
	up to the knees