bush vs shrub

bush and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
bush	Yes	Yes	Yes	No
shrub	Yes	No	No	No

As nouns, bush and shrub are synonyms defined as:

bush and shrub: a low woody perennial plant usually having several major stems

bush (noun)	shrub (noun)
hair growing in the pubic area	a low woody perennial plant usually having several major stems
dense vegetation consisting of stunted trees or bushes
a large wilderness area
a low woody perennial plant usually having several major stems

bush (adjective)	shrub (adjective)
not of the highest quality or sophistication

bush (verb)	shrub (verb)
provide with a bushing