demo vs demonstrate

demo is a noun but demonstrate is not a noun.

Word	Noun	Adjective	Verb	Adverb
demo	Yes	No	Yes	No
demonstrate	No	No	Yes	No

As verbs, demo and demonstrate are synonyms defined as:

Other synonyms of demo include exhibit, present, show.

demo (noun)	demonstrate (noun)
a visual presentation showing how something works

demo (verb)	demonstrate (verb)
give an exhibition of to an interested audience	establish the validity of something, as by an example, explanation or experiment
	provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes
	give an exhibition of to an interested audience
	march in protest; take part in a demonstration