climb down vs climb

climb down is not a noun while climb is a noun.

Word	Noun	Adjective	Verb	Adverb
climb down	No	No	Yes	No
climb	Yes	No	Yes	No

climb down (noun)	climb (noun)
	the act of climbing something
	an event that involves rising to a higher point (as in altitude or temperature or intensity etc.)
	an upward slope or grade (as in a road)

climb down (verb)	climb (verb)
come down	go up or advance
	increase in value or to a higher point
	improve one's social status
	go upward with gradual or continuous progress
	move with effort, by grasping
	slope upward