hop on vs hop

hop on is not a noun while hop is a noun.

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

hop on (noun)	hop (noun)
	the act of hopping; jumping upward or forward (especially on one foot)
	an informal dance where popular music is played
	twining perennials having cordate leaves and flowers arranged in conelike spikes; the dried flowers of this plant are used in brewing to add the characteristic bitter taste to beer

hop on (verb)	hop (verb)
get up on the back of	jump lightly
	make a jump forward or upward
	jump across
	traverse as if by a short airplane trip
	move quickly from one place to another
	travel by means of an aircraft, bus, etc.