climb vs climb on

climb is a noun but climb on is not a noun.

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

climb (noun)	climb on (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 (verb)	climb on (verb)
go up or advance	get up on the back of
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